Merge pull request hyperledger-web3j#585 from argentlabs/fix_NPE_issu…

…e402 fixed NPE when calling a view function in a contract that returns an out-of-gas error, issue 402
yuanfayang · Jun 11, 2018 · f28bc43 · f28bc43
2 parents 5827382 + 8480736
commit f28bc43
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Showing 3 changed files with 10 additions and 2 deletions.
diff --git a/abi/src/main/java/org/web3j/abi/FunctionReturnDecoder.java b/abi/src/main/java/org/web3j/abi/FunctionReturnDecoder.java
@@ -14,6 +14,7 @@
 import org.web3j.abi.datatypes.Utf8String;
 import org.web3j.abi.datatypes.generated.Bytes32;
 import org.web3j.utils.Numeric;
+import org.web3j.utils.Strings;
 
 import static org.web3j.abi.TypeDecoder.MAX_BYTE_LENGTH_FOR_HEX_STRING;
 
@@ -36,7 +37,7 @@ public static List<Type> decode(
             String rawInput, List<TypeReference<Type>> outputParameters) {
         String input = Numeric.cleanHexPrefix(rawInput);
 
-        if (input.isEmpty()) {
+        if (Strings.isEmpty(input)) {
             return Collections.emptyList();
         } else {
             return build(input, outputParameters);

diff --git a/utils/src/main/java/org/web3j/utils/Numeric.java b/utils/src/main/java/org/web3j/utils/Numeric.java
@@ -77,7 +77,8 @@ public static String prependHexPrefix(String input) {
     }
 
     public static boolean containsHexPrefix(String input) {
-        return input.length() > 1 && input.charAt(0) == '0' && input.charAt(1) == 'x';
+        return !Strings.isEmpty(input) && input.length() > 1
+                && input.charAt(0) == '0' && input.charAt(1) == 'x';
     }
 
     public static BigInteger toBigInt(byte[] value, int offset, int length) {

diff --git a/utils/src/test/java/org/web3j/utils/NumericTest.java b/utils/src/test/java/org/web3j/utils/NumericTest.java
@@ -225,4 +225,10 @@ public void testIsIntegerValue() {
         assertFalse(Numeric.isIntegerValue(BigDecimal.valueOf(1.1)));
         assertFalse(Numeric.isIntegerValue(BigDecimal.valueOf(-1.1)));
     }
+
+    @Test
+    public void testHandleNPE() {
+        assertFalse(Numeric.containsHexPrefix(null));
+        assertFalse(Numeric.containsHexPrefix(""));
+    }
 }