diff --git a/tests/cpp/security/CredentialGenerator.hpp b/tests/cpp/security/CredentialGenerator.hpp
index d35b4e380b..bf9661a0a8 100644
--- a/tests/cpp/security/CredentialGenerator.hpp
+++ b/tests/cpp/security/CredentialGenerator.hpp
@@ -129,11 +129,7 @@ class CredentialGenerator {
   ID id() { return m_id; }
   std::string name() { return m_name; }
 
-  std::string toString() {
-    char chID[5];
-    sprintf(chID, "%d", m_id);
-    return std::string(chID) + m_name;
-  }
+  std::string toString() { return std::to_string(m_id) + m_name; }
   static void dump();
 
   void hashCode() {}
@@ -141,18 +137,11 @@ class CredentialGenerator {
   void getAuthInit(std::shared_ptr<Properties>& prop);
 
   std::string getPublickeyfile() {
-    char* tempPath = nullptr;
-    tempPath = ACE_OS::getenv("TESTSRC");
-    std::string path = "";
-    if (!tempPath) {
-      tempPath = ACE_OS::getenv("BUILDDIR");
-      path = std::string(tempPath) + "/framework/data";
-    } else {
-      path = std::string(tempPath);
-    }
-    char pubfile[1000] = {'\0'};
-    sprintf(pubfile, "%s/keystore/publickeyfile", path.c_str());
-    return std::string(pubfile);
+    auto path =
+        ACE_OS::getenv("TESTSRC")
+            ? std::string(ACE_OS::getenv("TESTSRC"))
+            : std::string(ACE_OS::getenv("BUILDDIR")) + "/framework/data";
+    return path + "/keystore/publickeyfile";
   }
 
   std::string getServerCmdParams(std::string securityParams,
diff --git a/tests/cpp/security/PkcsCredentialGenerator.cpp b/tests/cpp/security/PkcsCredentialGenerator.cpp
index f09b19b9c2..1207bd4673 100644
--- a/tests/cpp/security/PkcsCredentialGenerator.cpp
+++ b/tests/cpp/security/PkcsCredentialGenerator.cpp
@@ -61,18 +61,14 @@ std::string PKCSCredentialGenerator::getInitArgs(std::string workingDir, bool) {
 
 void PKCSCredentialGenerator::getValidCredentials(
     std::shared_ptr<Properties>& p) {
-  char username[20] = {'\0'};
-  sprintf(username, "geode%d", randomValue(1, 10));
-  setPKCSProperties(p, username);
+  setPKCSProperties(p, "geode" + std::to_string(randomValue(1, 10)));
   BOOST_LOG_TRIVIAL(info) << "inserted valid security-username "
                           << p->find("security-username")->value();
 }
 
 void PKCSCredentialGenerator::getInvalidCredentials(
     std::shared_ptr<Properties>& p) {
-  char username[20] = {'\0'};
-  sprintf(username, "%dgeode", randomValue(1, 11));
-  setPKCSProperties(p, username);
+  setPKCSProperties(p, std::to_string(randomValue(1, 11)) + "geode");
   BOOST_LOG_TRIVIAL(info) << "inserted invalid security-username "
                           << p->find("security-username")->value();
 }
diff --git a/tests/cpp/security/PkcsCredentialGenerator.hpp b/tests/cpp/security/PkcsCredentialGenerator.hpp
index c3943f9d59..53f6e261ea 100644
--- a/tests/cpp/security/PkcsCredentialGenerator.hpp
+++ b/tests/cpp/security/PkcsCredentialGenerator.hpp
@@ -69,30 +69,19 @@ class PKCSCredentialGenerator : public CredentialGenerator {
   }
 
   void insertKeyStorePath(std::shared_ptr<Properties>& p,
-                          const char* username) {
-    char keystoreFilePath[1024];
-    char* tempPath = nullptr;
-    tempPath = ACE_OS::getenv("TESTSRC");
-    std::string path = "";
-    if (!tempPath) {
-      tempPath = ACE_OS::getenv("BUILDDIR");
-      path = std::string(tempPath) + "/framework/data";
-    } else {
-      path = std::string(tempPath);
-    }
-
-    sprintf(keystoreFilePath, "%s/keystore/%s.keystore", path.c_str(),
-            username);
-    p->insert(KEYSTORE_FILE_PATH, keystoreFilePath);
+                          const std::string& username) {
+    auto path =
+        ACE_OS::getenv("TESTSRC")
+            ? std::string(ACE_OS::getenv("TESTSRC"))
+            : std::string(ACE_OS::getenv("BUILDDIR")) + "/framework/data";
+    p->insert(KEYSTORE_FILE_PATH, path + "/keystore/" + username + ".keystore");
   }
 
-  void setPKCSProperties(std::shared_ptr<Properties>& p, char* username) {
-    char keyStorePassWord[1024];
-
-    sprintf(keyStorePassWord, "%s", "geode");
+  void setPKCSProperties(std::shared_ptr<Properties>& p,
+                         const std::string& username) {
     p->insert(SECURITY_USERNAME, "geode");
     p->insert(KEYSTORE_ALIAS, username);
-    p->insert(KEYSTORE_PASSWORD, keyStorePassWord);
+    p->insert(KEYSTORE_PASSWORD, "geode");
     insertKeyStorePath(p, username);
   }
 
diff --git a/tests/cpp/security/XmlAuthzCredentialGenerator.cpp b/tests/cpp/security/XmlAuthzCredentialGenerator.cpp
index 89cecd42ae..9226862bd5 100644
--- a/tests/cpp/security/XmlAuthzCredentialGenerator.cpp
+++ b/tests/cpp/security/XmlAuthzCredentialGenerator.cpp
@@ -46,22 +46,23 @@ void XmlAuthzCredentialGenerator::getAllowedDummyAuthz(ROLES role) {
     role = getRequiredRole();
     validity = "valid";
   }
-  char userName[100];
+
+  std::string userName;
   switch (role) {
     case READER_ROLE:
-      sprintf(userName, kPRiUsername, "reader", randomValue(2));
+      userName = "reader" + std::to_string(randomValue(2));
       break;
     case WRITER_ROLE:
-      sprintf(userName, kPRiUsername, "writer", randomValue(2));
+      userName = "writer" + std::to_string(randomValue(2));
       break;
     case QUERY_ROLE:
-      sprintf(userName, kPRiUsername, "reader", randomValue(1) + 3);
+      userName = "reader" + std::to_string(randomValue(1) + 3);
       break;
     case ADMIN_ROLE:
-      sprintf(userName, "%s", adminUsers[randomValue(adminUsrSz)]);
+      userName = adminUsers[randomValue(adminUsrSz)];
       break;
     case NO_ROLE:
-      sprintf(userName, kPRiUsername, "user", randomValue(2));
+      userName = "user" + std::to_string(randomValue(2));
       break;
   }
 
@@ -93,29 +94,29 @@ std::string XmlAuthzCredentialGenerator::getAllowedUser(ROLES role) {
     role = getRequiredRole();
     validity = "valid";
   }
-  char userName[256];
+  std::string userName;
   switch (role) {
     case READER_ROLE:
-      sprintf(userName, kPRiUsername, userPrefix.c_str(),
-              readerIndices[randomValue(readerIndSz)]);
+      userName =
+          userPrefix + std::to_string(readerIndices[randomValue(readerIndSz)]);
       break;
     case WRITER_ROLE:
-      sprintf(userName, kPRiUsername, userPrefix.c_str(),
-              writerIndices[randomValue(writerIndSz)]);
+      userName =
+          userPrefix + std::to_string(writerIndices[randomValue(writerIndSz)]);
       break;
     case QUERY_ROLE:
-      sprintf(userName, kPRiUsername, userPrefix.c_str(),
-              queryIndices[randomValue(queryIndSz)]);
+      userName =
+          userPrefix + std::to_string(queryIndices[randomValue(queryIndSz)]);
       break;
     case ADMIN_ROLE:
     case NO_ROLE:
-      sprintf(userName, kPRiUsername, userPrefix.c_str(),
-              adminIndices[randomValue(adminIndSz)]);
+      userName =
+          userPrefix + std::to_string(adminIndices[randomValue(adminIndSz)]);
       break;
   }
   BOOST_LOG_TRIVIAL(info) << "inserted " << validity << " username "
                           << userName;
-  return std::string(userName);
+  return userName;
 }
 
 void XmlAuthzCredentialGenerator::getAllowedLdapAuthz(ROLES role) {
diff --git a/tests/cpp/security/XmlAuthzCredentialGenerator.hpp b/tests/cpp/security/XmlAuthzCredentialGenerator.hpp
index 64545f05d8..c9f95e1f71 100644
--- a/tests/cpp/security/XmlAuthzCredentialGenerator.hpp
+++ b/tests/cpp/security/XmlAuthzCredentialGenerator.hpp
@@ -55,8 +55,6 @@ const opCodeList::value_type QArr[] = {OP_QUERY, OP_REGISTER_CQ};
 
 const stringList::value_type QRArr[] = {"Portfolios", "Positions"};
 
-static const char* kPRiUsername = "%s%d";
-
 class XmlAuthzCredentialGenerator;
 
 class XmlAuthzCredentialGenerator {
diff --git a/tests/cpp/testobject/BatchObject.cpp b/tests/cpp/testobject/BatchObject.cpp
index a2f8635fcf..c1ea92a5b2 100644
--- a/tests/cpp/testobject/BatchObject.cpp
+++ b/tests/cpp/testobject/BatchObject.cpp
@@ -17,6 +17,8 @@
 
 #include "BatchObject.hpp"
 
+#include <sstream>
+
 namespace testobject {
 
 using apache::geode::client::CacheableBytes;
@@ -42,12 +44,11 @@ void BatchObject::fromData(apache::geode::client::DataInput& input) {
   byteArray = std::dynamic_pointer_cast<CacheableBytes>(input.readObject());
 }
 std::string BatchObject::toString() const {
-  char buf[102500];
-  sprintf(buf,
-          "BatchObject:[index = %d timestamp = %" PRIu64
-          " batch = %d byteArray=%d ]",
-          index, timestamp, batch, byteArray->length());
-  return buf;
+  std::stringstream strm;
+
+  strm << "BatchObject:[index = " << index << " timestamp = " << timestamp
+       << " batch = " << batch << " byteArray = " << byteArray->length() << "]";
+  return strm.str();
 }
 
 }  // namespace testobject
diff --git a/tests/cpp/testobject/DeltaFastAssetAccount.hpp b/tests/cpp/testobject/DeltaFastAssetAccount.hpp
index 96620047a2..0a99ebc1f5 100644
--- a/tests/cpp/testobject/DeltaFastAssetAccount.hpp
+++ b/tests/cpp/testobject/DeltaFastAssetAccount.hpp
@@ -21,6 +21,7 @@
 #define GEODE_TESTOBJECT_DELTAFASTASSETACCOUNT_H_
 
 #include <cinttypes>
+#include <sstream>
 #include <string>
 
 #include <geode/CacheableBuiltins.hpp>
@@ -72,12 +73,12 @@ class TESTOBJECT_EXPORT DeltaFastAssetAccount : public DataSerializable,
   void fromDelta(apache::geode::client::DataInput& input) override;
 
   std::string toString() const override {
-    char buf[102500];
-    sprintf(buf,
-            "DeltaFastAssetAccount:[acctId = %d customerName = %s netWorth = "
-            "%f timestamp = %" PRIu64 "]",
-            acctId, customerName->toString().c_str(), netWorth, timestamp);
-    return buf;
+    std::stringstream strm;
+
+    strm << "DeltaFastAssetAccount:[acctId = " << acctId
+         << " customerName = " << customerName->toString()
+         << " netWorth = " << netWorth << " timestamp = " << timestamp << "]";
+    return strm.str();
   }
 
   int getAcctId() { return acctId; }
diff --git a/tests/cpp/testobject/DeltaPSTObject.cpp b/tests/cpp/testobject/DeltaPSTObject.cpp
index f055100336..e981393618 100644
--- a/tests/cpp/testobject/DeltaPSTObject.cpp
+++ b/tests/cpp/testobject/DeltaPSTObject.cpp
@@ -18,6 +18,7 @@
 #include "DeltaPSTObject.hpp"
 
 #include <fwklib/GsRandom.hpp>
+#include <sstream>
 
 #include "ArrayOfByte.hpp"
 
@@ -59,12 +60,12 @@ void DeltaPSTObject::fromData(apache::geode::client::DataInput& input) {
   valueData = std::dynamic_pointer_cast<CacheableBytes>(input.readObject());
 }
 std::string DeltaPSTObject::toString() const {
-  char buf[102500];
-  sprintf(buf,
-          "DeltaPSTObject:[timestamp = %" PRIu64
-          " field1 = %d field2 = %c valueData=%d ]",
-          timestamp, field1, field2, valueData->length());
-  return buf;
+  std::stringstream strm;
+
+  strm << "DeltaPSTObject:[timestamp = " << timestamp << " field1 = " << field1
+       << " field2 = " << field2 << " valueData = " << valueData->length()
+       << "]";
+  return strm.str();
 }
 
 }  // namespace testobject
diff --git a/tests/cpp/testobject/DeltaTestImpl.cpp b/tests/cpp/testobject/DeltaTestImpl.cpp
index 2babb2e5c9..db2301c6e4 100644
--- a/tests/cpp/testobject/DeltaTestImpl.cpp
+++ b/tests/cpp/testobject/DeltaTestImpl.cpp
@@ -17,6 +17,8 @@
 
 #include "DeltaTestImpl.hpp"
 
+#include <sstream>
+
 namespace testobject {
 
 uint8_t DeltaTestImpl::INT_MASK = 0x1;
@@ -128,10 +130,11 @@ void DeltaTestImpl::fromDelta(DataInput& input) {
 }
 
 std::string DeltaTestImpl::toString() const {
-  char buf[102500];
-  sprintf(buf, "DeltaTestImpl[hasDelta=%d int=%d double=%f str=%s \n",
-          m_hasDelta, intVar, doubleVar, str->toString().c_str());
-  return buf;
+  std::stringstream strm;
+
+  strm << "DeltaTestImpl[hasDelta=" << m_hasDelta << " int = " << intVar
+       << " double = " << doubleVar << " str = " << str->toString() << "\n";
+  return strm.str();
 }
 
 }  // namespace testobject
diff --git a/tests/cpp/testobject/DeltaTestObj.hpp b/tests/cpp/testobject/DeltaTestObj.hpp
index d6de7a046a..5c318fa95e 100644
--- a/tests/cpp/testobject/DeltaTestObj.hpp
+++ b/tests/cpp/testobject/DeltaTestObj.hpp
@@ -20,6 +20,8 @@
  * limitations under the License.
  */
 
+#include <sstream>
+
 #include "DeltaTestImpl.hpp"
 #include "testobject_export.h"
 
@@ -65,12 +67,12 @@ class TESTOBJECT_EXPORT DeltaTestObj : public DeltaTestImpl {
   void setFromDeltaCounter(int counter) { fromDeltaCounter = counter; }
   void setToDeltaCounter(int counter) { toDeltaCounter = counter; }
   std::string toString() const {
-    char buf[102500];
-    sprintf(buf,
-            "DeltaTestObj: toDeltaCounter = %lld fromDeltaCounter = %lld\n",
-            toDeltaCounter, fromDeltaCounter);
-    // DeltaTestImpl::toString();
-    return buf;
+    std::stringstream strm;
+
+    strm << "DeltaTestObj: toDeltaCounter = " << toDeltaCounter
+         << ", fromDeltaCounter = " << fromDeltaCounter << "\n";
+
+    return strm.str();
   }
   static Serializable* create() { return new DeltaTestObj(); }
   int32_t classId() const override { return 32; }
diff --git a/tests/cpp/testobject/EqStruct.cpp b/tests/cpp/testobject/EqStruct.cpp
index 30b31a361b..8fd99bbe55 100644
--- a/tests/cpp/testobject/EqStruct.cpp
+++ b/tests/cpp/testobject/EqStruct.cpp
@@ -17,6 +17,8 @@
 
 #include "EqStruct.hpp"
 
+#include <sstream>
+
 #include <geode/DataInput.hpp>
 #include <geode/DataOutput.hpp>
 
@@ -197,10 +199,11 @@ void EqStruct::fromData(apache::geode::client::DataInput& in) {
   discretionOffset = in.readDouble();
 }
 std::string EqStruct::toString() const {
-  char buf[102500];
-  sprintf(buf, "EqStruct:[timestamp = %" PRIu64 " myIndex = %d cxlQty = %d ]",
-          timestamp, myIndex, cxlQty);
-  return buf;
+  std::stringstream strm;
+
+  strm << "EqStruct:[timestamp = " << timestamp << " myIndex = " << myIndex
+       << " cxlQty = " << cxlQty << "]";
+  return strm.str();
 }
 
 }  // namespace testobject
diff --git a/tests/cpp/testobject/EqStruct.hpp b/tests/cpp/testobject/EqStruct.hpp
index 0e33539d0a..120ff9c0fa 100644
--- a/tests/cpp/testobject/EqStruct.hpp
+++ b/tests/cpp/testobject/EqStruct.hpp
@@ -108,9 +108,9 @@ class TESTOBJECT_EXPORT EqStruct : public TimestampedObject {
   void validate(int index) {
     int encodedIndex = myIndex;
     if (encodedIndex != index) {
-      char logmsg[2048];
-      sprintf(logmsg, "Expected index %d , got %d.\n", index, encodedIndex);
-      throw FwkException(logmsg);
+      throw FwkException(std::string("Expected index ") +
+                         std::to_string(index) + ", got " +
+                         std::to_string(encodedIndex) + ".\n");
     }
   }
   void update() {
diff --git a/tests/cpp/testobject/FastAssetAccount.cpp b/tests/cpp/testobject/FastAssetAccount.cpp
index 3946e69742..bbcbb106cf 100644
--- a/tests/cpp/testobject/FastAssetAccount.cpp
+++ b/tests/cpp/testobject/FastAssetAccount.cpp
@@ -18,6 +18,7 @@
 #include "FastAssetAccount.hpp"
 
 #include <cinttypes>
+#include <sstream>
 
 #include "FastAsset.hpp"
 
@@ -62,12 +63,12 @@ void FastAssetAccount::fromData(apache::geode::client::DataInput& input) {
 }
 
 std::string FastAssetAccount::toString() const {
-  char buf[102500];
-  sprintf(buf,
-          "FastAssetAccount:[acctId = %d customerName = %s netWorth = %f "
-          "timestamp = %" PRIu64 "]",
-          acctId, customerName->toString().c_str(), netWorth, timestamp);
-  return buf;
+  std::stringstream strm;
+
+  strm << "FastAssetAccount:[acctId = " << acctId
+       << " customerName = " << customerName->toString()
+       << " netWorth = " << netWorth << "timestamp = " << timestamp;
+  return strm.str();
 }
 
 }  // namespace testobject
diff --git a/tests/cpp/testobject/InvalidPdxUsage.cpp b/tests/cpp/testobject/InvalidPdxUsage.cpp
index 5532250026..1f49653b26 100644
--- a/tests/cpp/testobject/InvalidPdxUsage.cpp
+++ b/tests/cpp/testobject/InvalidPdxUsage.cpp
@@ -744,12 +744,7 @@ void InvalidPdxUsage::fromData(PdxReader& pr) {
       fromDataexceptionCounter, exceptionCounter);
 }
 std::string InvalidPdxUsage::toString() const {
-  char idbuf[1024];
-  // sprintf(idbuf,"PdxObject: [ m_bool=%d ] [m_byte=%d] [m_int16=%d]
-  // [m_int32=%d] [m_float=%f] [m_double=%lf] [ m_string=%s ]",m_bool, m_byte,
-  // m_int16, m_int32, m_float, m_double, m_string);
-  sprintf(idbuf, "PdxObject:[m_int32=%d]", m_int32);
-  return idbuf;
+  return "PdxObject:[m_int32=" + std::to_string(m_int32) + "]";
 }
 
 bool InvalidPdxUsage::equals(PdxTests::InvalidPdxUsage& other,
diff --git a/tests/cpp/testobject/InvalidPdxUsage.hpp b/tests/cpp/testobject/InvalidPdxUsage.hpp
index 1be93f9079..bab9579ee3 100644
--- a/tests/cpp/testobject/InvalidPdxUsage.hpp
+++ b/tests/cpp/testobject/InvalidPdxUsage.hpp
@@ -26,6 +26,7 @@
  *      Author: npatel
  */
 
+#include <sstream>
 #include <util/Log.hpp>
 
 #include <geode/CacheableEnum.hpp>
@@ -75,9 +76,10 @@ class TESTOBJECT_EXPORT CharTypesWithInvalidUsage : public PdxSerializable {
   CharTypesWithInvalidUsage() { init(); }
 
   std::string toString() const override {
-    char idbuf[1024];
-    sprintf(idbuf, "%c %c %c", m_ch, m_chArray[0], m_chArray[1]);
-    return idbuf;
+    std::stringstream strm;
+
+    strm << m_ch << " " << m_chArray[0] << " " << m_chArray[1];
+    return strm.str();
   }
 
   bool equals(CharTypesWithInvalidUsage& other) const {
diff --git a/tests/cpp/testobject/NestedPdxObject.cpp b/tests/cpp/testobject/NestedPdxObject.cpp
index 44fc86e5fa..8e8b404186 100644
--- a/tests/cpp/testobject/NestedPdxObject.cpp
+++ b/tests/cpp/testobject/NestedPdxObject.cpp
@@ -21,6 +21,8 @@
 
 #include "NestedPdxObject.hpp"
 
+#include <sstream>
+
 namespace testobject {
 
 void ChildPdx::toData(PdxWriter& pw) const {
@@ -107,11 +109,12 @@ void ParentPdx::fromData(PdxReader& pr) {
 }
 
 std::string ParentPdx::toString() const {
-  char idbuf[1024];
-  sprintf(idbuf,
-          "ParentPdx: [m_parentId=%d] [ m_parentName=%s ] [m_childPdx = %s ] ",
-          m_parentId, m_parentName.c_str(), m_childPdx->toString().c_str());
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "ParentPdx: [m_parentId=" << m_parentId
+       << "][m_parentName = " << m_parentName << "][m_childPdx = " << m_childPdx
+       << "] ";
+  return strm.str();
 }
 
 bool ParentPdx::equals(const ParentPdx& other, bool isPdxReadSerialized) const {
diff --git a/tests/cpp/testobject/PSTObject.cpp b/tests/cpp/testobject/PSTObject.cpp
index d9e55ef180..465554b666 100644
--- a/tests/cpp/testobject/PSTObject.cpp
+++ b/tests/cpp/testobject/PSTObject.cpp
@@ -18,6 +18,7 @@
 #include "PSTObject.hpp"
 
 #include <fwklib/GsRandom.hpp>
+#include <sstream>
 
 #include "ArrayOfByte.hpp"
 
@@ -49,12 +50,12 @@ void PSTObject::fromData(apache::geode::client::DataInput& input) {
   valueData = std::dynamic_pointer_cast<CacheableBytes>(input.readObject());
 }
 std::string PSTObject::toString() const {
-  char buf[102500];
-  sprintf(buf,
-          "PSTObject:[timestamp = %" PRIu64
-          " field1 = %d field2 = %c valueData=%d ]",
-          timestamp, field1, field2, valueData->length());
-  return buf;
+  std::stringstream strm;
+
+  strm << "PSTObject:[timestamp = " << timestamp << " field1 = " << field1
+       << " field2 = " << field2 << " valueData = " << valueData->length()
+       << "]";
+  return strm.str();
 }
 
 }  // namespace testobject
diff --git a/tests/cpp/testobject/PdxClassV1.cpp b/tests/cpp/testobject/PdxClassV1.cpp
index 830e07f698..23b07ccd9d 100644
--- a/tests/cpp/testobject/PdxClassV1.cpp
+++ b/tests/cpp/testobject/PdxClassV1.cpp
@@ -17,6 +17,8 @@
 
 #include "PdxClassV1.hpp"
 
+#include <sstream>
+
 namespace PdxTests {
 
 using apache::geode::client::Exception;
@@ -145,19 +147,11 @@ void PdxType1V1::fromData(PdxReader& pr) {
   LOGDEBUG("PdxObject::fromData() End...");
 }
 std::string PdxType1V1::toString() const {
-  char idbuf[4096];
-  // sprintf(idbuf,"PdxObject: [ m_bool=%d ] [m_byte=%d] [m_int16=%d]
-  // [m_int32=%d] [m_long=%lld] [m_float=%f] [ m_string=%s ]",m_bool, m_byte,
-  // m_int16, m_int32, m_long, m_float, m_string);
-  // sprintf(idbuf,"PdxObject: [ m_bool=%d ] [m_byte=%d] [m_int16=%d]
-  // [m_int32=%d] [m_long=%lld] [m_float=%f] [m_double=%Lf] [ m_string=%s
-  // ]",m_bool, m_byte, m_int16, m_int32, m_long, m_float, m_double, m_string);
-  // sprintf(idbuf,"PdxObject: [ m_bool=%d ] [m_byte=%d] [m_int16=%d]
-  // [m_int32=%d] [m_float=%f] [m_double=%lf] [ m_string=%s ]",m_bool, m_byte,
-  // m_int16, m_int32, m_float, m_double, m_string);
-  sprintf(idbuf, "PdxType1V1:[ m_i1=%d ] [ m_i2=%d ] [ m_i3=%d ] [ m_i4=%d ]",
-          m_i1, m_i2, m_i3, m_i4);
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxType1V1:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]";
+  return strm.str();
 }
 
 /************************************************************
@@ -226,10 +220,11 @@ void PdxType2V1::fromData(PdxReader& pr) {
   m_i4 = pr.readInt("i4");
 }
 std::string PdxType2V1::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf, "PdxType2V1:[ m_i1=%d ] [ m_i2=%d ] [ m_i3=%d ] [ m_i4=%d ]",
-          m_i1, m_i2, m_i3, m_i4);
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxType2V1:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]";
+  return strm.str();
 }
 
 /************************************************************
@@ -392,10 +387,11 @@ void PdxTypesV1R1::fromData(PdxReader& pr) {
   m_i4 = pr.readInt("i4");
 }
 std::string PdxTypesV1R1::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf, "PdxTypesV1R1:[ m_i1=%d ] [ m_i2=%d ] [ m_i3=%d ] [ m_i4=%d ]",
-          m_i1, m_i2, m_i3, m_i4);
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypesV1R1:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]";
+  return strm.str();
 }
 
 /************************************************************
@@ -461,10 +457,11 @@ void PdxTypesV1R2::fromData(PdxReader& pr) {
   m_i4 = pr.readInt("i4");
 }
 std::string PdxTypesV1R2::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf, "PdxTypesV1R1:[ m_i1=%d ] [ m_i2=%d ] [ m_i3=%d ] [ m_i4=%d ]",
-          m_i1, m_i2, m_i3, m_i4);
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypesV1R2:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]";
+  return strm.str();
 }
 
 /************************************************************
@@ -541,10 +538,12 @@ void PdxTypesIgnoreUnreadFieldsV1::fromData(PdxReader& pr) {
   if (!hasField) throw Exception("i4 is an valid field");
 }
 std::string PdxTypesIgnoreUnreadFieldsV1::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf, "PdxTypesV1R1:[ m_i1=%d ] [ m_i2=%d ] [ m_i3=%d ] [ m_i4=%d ]",
-          m_i1, m_i2, m_i3, m_i4);
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypesIgnoreUnreadFieldsV1:[m_i1 = " << m_i1
+       << " ][m_i2 = " << m_i2 << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4
+       << "]";
+  return strm.str();
 }
 
 /************************************************************
@@ -648,12 +647,7 @@ void PdxVersionedV1::fromData(PdxReader& pr) {
   m_floatArray = pr.readFloatArray("m_floatArray");
   m_doubleArray = pr.readDoubleArray("m_doubleArray");
 }
-std::string PdxVersionedV1::toString() const {
-  char idbuf[4096];
-  // sprintf(idbuf,"PdxTypesV1R1:[ m_i1=%d ] [ m_i2=%d ] [ m_i3=%d ] [ m_i4=%d
-  // ]", m_i1, m_i2, m_i3, m_i4 );
-  return idbuf;
-}
+std::string PdxVersionedV1::toString() const { return ""; }
 
 /************************************************************
  *  TestKey
@@ -717,9 +711,10 @@ void TestEqualsV1::fromData(PdxReader& pr) {
   // sArr = (string[]) reader.ReadObject("sArrObject");
 }
 std::string TestEqualsV1::toString() const {
-  char idbuf[1024];
-  sprintf(idbuf, "TestEqualsV1:[i1=%d ] [i2=%d] ", i1, i2);
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "TestEqualsV1:[i1 = " << i1 << " ][i2 = " << i2 << "]";
+  return strm.str();
 }
 
 }  // namespace PdxTests
diff --git a/tests/cpp/testobject/PdxClassV2.cpp b/tests/cpp/testobject/PdxClassV2.cpp
index 624d571d58..de717f3651 100644
--- a/tests/cpp/testobject/PdxClassV2.cpp
+++ b/tests/cpp/testobject/PdxClassV2.cpp
@@ -17,6 +17,8 @@
 
 #include "PdxClassV2.hpp"
 
+#include <sstream>
+
 namespace PdxTests {
 
 using apache::geode::client::Exception;
@@ -106,12 +108,13 @@ void PdxTypes1V2::fromData(PdxReader& pr) {
   // LOGDEBUG("PdxType1V2::fromData() End...");
 }
 std::string PdxTypes1V2::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf,
-          "PdxType1V1:[ m_i1=%d ] [ m_i2=%d ] [ m_i3=%d ] [ m_i4=%d ] [ "
-          "m_i5=%d ] [ m_i6=%d ] [ m_diffInExtraFields=%d ]",
-          m_i1, m_i2, m_i3, m_i4, m_i5, m_i6, m_diffInExtraFields);
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypes1V2:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]"
+       << "[m_i5 = " << m_i5 << "][m_i6 = " << m_i6
+       << "][m_diffInExtraFields = " << m_diffInExtraFields << "]";
+  return strm.str();
 }
 
 /************************************************************
@@ -193,12 +196,12 @@ void PdxTypes2V2::fromData(PdxReader& pr) {
   m_i4 = pr.readInt("i4");
 }
 std::string PdxTypes2V2::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf,
-          "PdxTypes2V2:[ m_i1=%d ] [ m_i2=%d ] [ m_i3=%d ] [ m_i4=%d ] [ "
-          "m_i5=%d ] [ m_i6=%d ]",
-          m_i1, m_i2, m_i3, m_i4, m_i5, m_i6);
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypes2V2:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]"
+       << "[m_i5 = " << m_i5 << "][m_i6 = " << m_i6 << "]";
+  return strm.str();
 }
 
 /************************************************************
@@ -379,12 +382,12 @@ void PdxTypesR1V2::fromData(PdxReader& pr) {
   m_i6 = pr.readInt("i6");
 }
 std::string PdxTypesR1V2::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf,
-          "PdxTypesR1V2:[ m_i1=%d ] [ m_i2=%d ] [ m_i3=%d ] [ m_i4=%d ] [ "
-          "m_i5=%d ] [ m_i6=%d ]",
-          m_i1, m_i2, m_i3, m_i4, m_i5, m_i6);
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypesR1V2:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]"
+       << "[m_i5 = " << m_i5 << "][m_i6 = " << m_i6 << "]";
+  return strm.str();
 }
 
 /************************************************************
@@ -456,9 +459,7 @@ void PdxTypesR2V2::toData(PdxWriter& pw) const {
   m_diffInExtraFields++;
   m_diffInSameFields++;
 
-  char tmpBuf[512] = {0};
-  sprintf(tmpBuf, "%d", m_diffInExtraFields);
-  pw.writeString("m_str1", tmpBuf);
+  pw.writeString("m_str1", std::to_string(m_diffInExtraFields));
 }
 
 void PdxTypesR2V2::fromData(PdxReader& pr) {
@@ -587,12 +588,13 @@ void PdxTypesIgnoreUnreadFieldsV2::fromData(PdxReader& pr) {
   m_i6 = pr.readInt("i6");
 }
 std::string PdxTypesIgnoreUnreadFieldsV2::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf,
-          "PdxTypesV1R1:[m_i1=%d] [m_i2=%d] [m_i3=%d] [m_i4=%d] [m_i5=%d] "
-          "[m_i6=%d]",
-          m_i1, m_i2, m_i3, m_i4, m_i5, m_i6);
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypesIgnoreUnreadFieldsV2:[m_i1 = " << m_i1
+       << " ][m_i2 = " << m_i2 << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4
+       << "]"
+       << "[m_i5 = " << m_i5 << "][m_i6 = " << m_i6 << "]";
+  return strm.str();
 }
 
 /************************************************************
@@ -694,12 +696,7 @@ void PdxVersionedV2::fromData(PdxReader& pr) {
   m_floatArray = pr.readFloatArray("m_floatArray");
   m_doubleArray = pr.readDoubleArray("m_doubleArray");
 }
-std::string PdxVersionedV2::toString() const {
-  char idbuf[4096];
-  // sprintf(idbuf,"PdxTypesV1R1:[ m_i1=%d ] [ m_i2=%d ] [ m_i3=%d ] [ m_i4=%d
-  // ]", m_i1, m_i2, m_i3, m_i4 );
-  return idbuf;
-}
+std::string PdxVersionedV2::toString() const { return ""; }
 
 /************************************************************
  *  TestKeyV2
diff --git a/tests/cpp/testobject/PdxType.cpp b/tests/cpp/testobject/PdxType.cpp
index 1b734c2f2c..e998375ca1 100644
--- a/tests/cpp/testobject/PdxType.cpp
+++ b/tests/cpp/testobject/PdxType.cpp
@@ -259,12 +259,7 @@ void PdxTests::PdxType::fromData(PdxReader& pr) {
   LOGINFO("PdxObject::readObject() for enum Done...");
 }
 std::string PdxTests::PdxType::toString() const {
-  char idbuf[1024];
-  // sprintf(idbuf,"PdxObject: [ m_bool=%d ] [m_byte=%d] [m_int16=%d]
-  // [m_int32=%d] [m_float=%f] [m_double=%lf] [ m_string=%s ]",m_bool, m_byte,
-  // m_int16, m_int32, m_float, m_double, m_string);
-  sprintf(idbuf, "PdxObject:[m_int32=%d]", m_int32);
-  return idbuf;
+  return "PdxObject:[m_int32=" + std::to_string(m_int32) + "]";
 }
 
 bool PdxTests::PdxType::equals(PdxTests::PdxType& other,
diff --git a/tests/cpp/testobject/PdxType.hpp b/tests/cpp/testobject/PdxType.hpp
index 390cfc676a..665f6ecb9f 100644
--- a/tests/cpp/testobject/PdxType.hpp
+++ b/tests/cpp/testobject/PdxType.hpp
@@ -20,6 +20,7 @@
 #ifndef GEODE_TESTOBJECT_PDXTYPE_H_
 #define GEODE_TESTOBJECT_PDXTYPE_H_
 
+#include <sstream>
 #include <util/Log.hpp>
 
 #include <geode/CacheableEnum.hpp>
@@ -106,9 +107,11 @@ class TESTOBJECT_EXPORT Child : public Parent, public PdxSerializable {
   int32_t getMember_f() { return m_f; }
 
   std::string toString() const override {
-    char idbuf[512];
-    sprintf(idbuf, " Child:: %d %d %d %d %d %d ", m_a, m_b, m_c, m_d, m_e, m_f);
-    return idbuf;
+    std::stringstream strm;
+
+    strm << "Child:: " << m_a << " " << m_b << " " << m_c << " " << m_d << " "
+         << m_e << " " << m_f;
+    return strm.str();
   }
 
   const std::string& getClassName() const override {
@@ -179,9 +182,10 @@ class TESTOBJECT_EXPORT CharTypes : public PdxSerializable {
   CharTypes() { init(); }
 
   std::string toString() const override {
-    char idbuf[1024];
-    sprintf(idbuf, "%c %c %c", m_ch, m_chArray[0], m_chArray[1]);
-    return idbuf;
+    std::stringstream strm;
+
+    strm << m_ch << " " << m_chArray[0] << " " << m_chArray[1];
+    return strm.str();
   }
 
   bool equals(CharTypes& other) const {
diff --git a/tests/cpp/testobject/Position.cpp b/tests/cpp/testobject/Position.cpp
index 36b3364295..8b491dbe81 100644
--- a/tests/cpp/testobject/Position.cpp
+++ b/tests/cpp/testobject/Position.cpp
@@ -14,11 +14,13 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 #include "Position.hpp"
 
 #include <wchar.h>
 
 #include <cwchar>
+#include <sstream>
 
 #include <geode/DataInput.hpp>
 #include <geode/DataOutput.hpp>
@@ -113,12 +115,12 @@ void Position::fromData(apache::geode::client::DataInput& input) {
   pid = input.readInt32();
 }
 std::string Position::toString() const {
-  char buf[2048];
-  sprintf(buf,
-          "Position Object:[ secId=%s type=%ls sharesOutstanding=%d id=%d ]",
-          secId->toString().c_str(), this->secType.c_str(),
-          this->sharesOutstanding, this->pid);
-  return buf;
+  std::stringstream strm;
+
+  strm << "Position Object:[ secId=" << secId->toString()
+       << " type=" << std::string(secType.begin(), secType.end())
+       << " sharesOutstanding=" << sharesOutstanding << " id=" << pid << " ]";
+  return strm.str();
 }
 
 }  // namespace testobject
diff --git a/tests/cpp/testobject/PositionPdx.cpp b/tests/cpp/testobject/PositionPdx.cpp
index a680663b97..83b1d1d236 100644
--- a/tests/cpp/testobject/PositionPdx.cpp
+++ b/tests/cpp/testobject/PositionPdx.cpp
@@ -141,8 +141,7 @@ void PositionPdx::fromData(PdxReader& pr) {
 }
 std::string PositionPdx::toString() const {
   char buf[1024];
-  sprintf(buf, "PositionPdx Object:[ id=%d ]", this->pid);
-  return buf;
+  return "PositionPdx Object:[ id=" + std::to_string(pid) + "]";
 }
 
 }  // namespace testobject
diff --git a/tests/cpp/testobject/VariousPdxTypes.cpp b/tests/cpp/testobject/VariousPdxTypes.cpp
index a3f9ede8e7..12812f4458 100644
--- a/tests/cpp/testobject/VariousPdxTypes.cpp
+++ b/tests/cpp/testobject/VariousPdxTypes.cpp
@@ -23,6 +23,7 @@
 
 #include "VariousPdxTypes.hpp"
 
+#include <sstream>
 #include <util/Log.hpp>
 
 #include <geode/CacheableEnum.hpp>
@@ -74,10 +75,11 @@ bool PdxTypes1::equals(std::shared_ptr<PdxSerializable> obj) {
   return false;
 }
 std::string PdxTypes1::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf, "PdxTypes1:[m_i1=%d] [m_i2=%d] [m_i3=%d] [m_i4=%d]", m_i1,
-          m_i2, m_i3, m_i4);
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypes1:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]";
+  return strm.str();
 }
 
 void PdxTypes1::toData(PdxWriter &pw) const {
@@ -131,10 +133,12 @@ bool PdxTypes2::equals(std::shared_ptr<PdxSerializable> obj) {
   return false;
 }
 std::string PdxTypes2::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf, "PdxTypes2:[m_i1=%d] [m_i2=%d] [m_i3=%d] [m_i4=%d] [m_s1=%s]",
-          m_i1, m_i2, m_i3, m_i4, m_s1.c_str());
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypes2:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "][m_s1 = " << m_s1
+       << "]";
+  return strm.str();
 }
 
 void PdxTypes2::toData(PdxWriter &pw) const {
@@ -187,10 +191,12 @@ bool PdxTypes3::equals(std::shared_ptr<PdxSerializable> obj) {
   return false;
 }
 std::string PdxTypes3::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf, "PdxTypes3:[m_i1=%d] [m_i2=%d] [m_i3=%d] [m_i4=%d] [m_s1=%s]",
-          m_i1, m_i2, m_i3, m_i4, m_s1.c_str());
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypes3:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "][m_s1 = " << m_s1
+       << "]";
+  return strm.str();
 }
 
 void PdxTypes3::toData(PdxWriter &pw) const {
@@ -243,10 +249,12 @@ bool PdxTypes4::equals(std::shared_ptr<PdxSerializable> obj) {
   return false;
 }
 std::string PdxTypes4::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf, "PdxTypes4:[m_i1=%d] [m_i2=%d] [m_i3=%d] [m_i4=%d] [m_s1=%s]",
-          m_i1, m_i2, m_i3, m_i4, m_s1.c_str());
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypes4:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "][m_s1 = " << m_s1
+       << "]";
+  return strm.str();
 }
 
 void PdxTypes4::toData(PdxWriter &pw) const {
@@ -300,12 +308,12 @@ bool PdxTypes5::equals(std::shared_ptr<PdxSerializable> obj) {
   return false;
 }
 std::string PdxTypes5::toString() const {
-  char idbuf[4096];
-  sprintf(
-      idbuf,
-      "PdxTypes4:[m_i1=%d] [m_i2=%d] [m_i3=%d] [m_i4=%d] [m_s1=%s] [m_s2=%s]",
-      m_i1, m_i2, m_i3, m_i4, m_s1.c_str(), m_s2.c_str());
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypes5:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]"
+       << "[m_s1 = " << m_s1 << "][m_s2 = " << m_s2 << "]";
+  return strm.str();
 }
 
 void PdxTypes5::toData(PdxWriter &pw) const {
@@ -381,12 +389,12 @@ bool PdxTypes6::equals(std::shared_ptr<PdxSerializable> obj) {
   return false;
 }
 std::string PdxTypes6::toString() const {
-  char idbuf[4096];
-  sprintf(
-      idbuf,
-      "PdxTypes4:[m_i1=%d] [m_i2=%d] [m_i3=%d] [m_i4=%d] [m_s1=%s] [m_s2=%s]",
-      m_i1, m_i2, m_i3, m_i4, m_s1.c_str(), m_s2.c_str());
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypes6:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]"
+       << "[m_s1 = " << m_s1 << "][m_s2 = " << m_s2 << "]";
+  return strm.str();
 }
 
 void PdxTypes6::toData(PdxWriter &pw) const {
@@ -457,12 +465,12 @@ bool PdxTypes7::equals(std::shared_ptr<PdxSerializable> obj) {
   return false;
 }
 std::string PdxTypes7::toString() const {
-  char idbuf[4096];
-  sprintf(
-      idbuf,
-      "PdxTypes7:[m_i1=%d] [m_i2=%d] [m_i3=%d] [m_i4=%d] [m_s1=%s] [m_s2=%s]",
-      m_i1, m_i2, m_i3, m_i4, m_s1.c_str(), m_s2.c_str());
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypes7:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]"
+       << "[m_s1 = " << m_s1 << "][m_s2 = " << m_s2 << "]";
+  return strm.str();
 }
 
 void PdxTypes7::toData(PdxWriter &pw) const {
@@ -521,12 +529,12 @@ bool PdxTypes8::equals(std::shared_ptr<PdxSerializable> obj) {
   return false;
 }
 std::string PdxTypes8::toString() const {
-  char idbuf[4096];
-  sprintf(
-      idbuf,
-      "PdxTypes8:[m_i1=%d] [m_i2=%d] [m_i3=%d] [m_i4=%d] [m_s1=%s] [m_s2=%s]",
-      m_i1, m_i2, m_i3, m_i4, m_s1.c_str(), m_s2.c_str());
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypes8:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]"
+       << "[m_s1 = " << m_s1 << "][m_s2 = " << m_s2 << "]";
+  return strm.str();
 }
 
 void PdxTypes8::toData(PdxWriter &pw) const {
@@ -584,10 +592,12 @@ bool PdxTypes9::equals(std::shared_ptr<PdxSerializable> obj) {
   return false;
 }
 std::string PdxTypes9::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf, "PdxTypes9:[m_s1=%s] [m_s2=%s] [m_s3=%s] [m_s4=%s] [m_s5=%s] ",
-          m_s1.c_str(), m_s2.c_str(), m_s3.c_str(), m_s4.c_str(), m_s5.c_str());
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypes9:[m_s1 = " << m_s1 << " ][m_s2 = " << m_s2
+       << "][m_s3 = " << m_s3 << "][m_s4 = " << m_s4 << "]"
+       << "[m_s5 = " << m_s5 << "]";
+  return strm.str();
 }
 
 void PdxTypes9::toData(PdxWriter &pw) const {
@@ -641,10 +651,12 @@ bool PdxTypes10::equals(std::shared_ptr<PdxSerializable> obj) {
   return false;
 }
 std::string PdxTypes10::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf, "PdxTypes9:[m_s1=%s] [m_s2=%s] [m_s3=%s] [m_s4=%s] [m_s5=%s] ",
-          m_s1.c_str(), m_s2.c_str(), m_s3.c_str(), m_s4.c_str(), m_s5.c_str());
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxTypes10:[m_s1 = " << m_s1 << " ][m_s2 = " << m_s2
+       << "][m_s3 = " << m_s3 << "][m_s4 = " << m_s4 << "]"
+       << "[m_s5 = " << m_s5 << "]";
+  return strm.str();
 }
 
 void PdxTypes10::toData(PdxWriter &pw) const {
@@ -714,12 +726,12 @@ bool NestedPdx::equals(std::shared_ptr<PdxSerializable> obj) {
   return false;
 }
 std::string NestedPdx::toString() const {
-  char idbuf[4096];
-  sprintf(
-      idbuf,
-      "NestedPdx:[m_i1=%d] [m_i2=%d] [m_i3=%d] [m_i4=%d] [m_s1=%s] [m_s2=%s]",
-      m_i1, m_i2, m_i3, m_i4, m_s1.c_str(), m_s2.c_str());
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "NestedPdx:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]"
+       << "[m_s1 = " << m_s1 << "][m_s2 = " << m_s2 << "]";
+  return strm.str();
 }
 
 void NestedPdx::toData(PdxWriter &pw) const {
@@ -795,12 +807,12 @@ bool MixedVersionNestedPdx::equals(std::shared_ptr<PdxSerializable> obj) {
   return false;
 }
 std::string MixedVersionNestedPdx::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf,
-          "MixedVersionNestedPdx:[m_i1=%d] [m_i2=%d] [m_i3=%d] [m_i4=%d] "
-          "[m_s1=%s] [m_s2=%s]",
-          m_i1, m_i2, m_i3, m_i4, m_s1.c_str(), m_s2.c_str());
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "MixedVersionNestedPdx:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]"
+       << "[m_s1 = " << m_s1 << "][m_s2 = " << m_s2 << "]";
+  return strm.str();
 }
 
 void MixedVersionNestedPdx::toData(PdxWriter &pw) const {
@@ -865,12 +877,12 @@ bool PdxInsideIGeodeSerializable::equals(std::shared_ptr<Serializable> obj) {
   return false;
 }
 std::string PdxInsideIGeodeSerializable::toString() const {
-  char idbuf[4096];
-  sprintf(idbuf,
-          "PdxInsideIGeodeSerializable:[m_i1=%d] [m_i2=%d] [m_i3=%d] [m_i4=%d] "
-          "[m_s1=%s] [m_s2=%s]",
-          m_i1, m_i2, m_i3, m_i4, m_s1.c_str(), m_s2.c_str());
-  return idbuf;
+  std::stringstream strm;
+
+  strm << "PdxInsideIGeodeSerializable:[m_i1 = " << m_i1 << " ][m_i2 = " << m_i2
+       << "][m_i3 = " << m_i3 << "][m_i4 = " << m_i4 << "]"
+       << "[m_s1 = " << m_s1 << "][m_s2 = " << m_s2 << "]";
+  return strm.str();
 }
 
 void PdxInsideIGeodeSerializable::toData(DataOutput &output) const {