diff --git a/core-java/pom.xml b/core-java/pom.xml index 42e3219ac315..0b69685e14a7 100644 --- a/core-java/pom.xml +++ b/core-java/pom.xml @@ -173,6 +173,19 @@ c3p0 ${c3p0.version} + + + org.javassist + javassist + ${javaassist.version} + + + com.sun + tools + 1.8.0 + system + ${java.home}/../lib/tools.jar + @@ -400,6 +413,111 @@ + + + + buildAgentLoader + + + + org.apache.maven.plugins + maven-jar-plugin + + + package + + jar + + + agentLoader + target/classes + + + true + + ${project.build.outputDirectory}/META-INF/MANIFEST.MF + + + + com/baeldung/instrumentation/application/AgentLoader.class + com/baeldung/instrumentation/application/Launcher.class + + + + + + + + + + buildApplication + + + + org.apache.maven.plugins + maven-jar-plugin + + + package + + jar + + + application + target/classes + + + true + + ${project.build.outputDirectory}/META-INF/MANIFEST.MF + + + + com/baeldung/instrumentation/application/MyAtm.class + com/baeldung/instrumentation/application/MyAtmApplication.class + com/baeldung/instrumentation/application/Launcher.class + + + + + + + + + + buildAgent + + + + org.apache.maven.plugins + maven-jar-plugin + + + package + + jar + + + agent + target/classes + + + true + + ${project.build.outputDirectory}/META-INF/MANIFEST.MF + + + + com/baeldung/instrumentation/agent/AtmTransformer.class + com/baeldung/instrumentation/agent/MyInstrumentationAgent.class + + + + + + + + @@ -453,6 +571,8 @@ 1.18 0.1.5 + + 3.21.0-GA diff --git a/core-java/src/main/java/com/baeldung/instrumentation/agent/AtmTransformer.java b/core-java/src/main/java/com/baeldung/instrumentation/agent/AtmTransformer.java new file mode 100644 index 000000000000..3c83912f5434 --- /dev/null +++ b/core-java/src/main/java/com/baeldung/instrumentation/agent/AtmTransformer.java @@ -0,0 +1,70 @@ +package com.baeldung.instrumentation.agent; + +import javassist.CannotCompileException; +import javassist.ClassPool; +import javassist.CtClass; +import javassist.CtMethod; +import javassist.NotFoundException; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.lang.instrument.ClassFileTransformer; +import java.lang.instrument.IllegalClassFormatException; +import java.security.ProtectionDomain; + +public class AtmTransformer implements ClassFileTransformer { + + private static Logger LOGGER = LoggerFactory.getLogger(AtmTransformer.class); + + private static final String WITHDRAW_MONEY_METHOD = "withdrawMoney"; + + /** The internal form class name of the class to transform */ + private String targetClassName; + /** The class loader of the class we want to transform */ + private ClassLoader targetClassLoader; + + public AtmTransformer(String targetClassName, ClassLoader targetClassLoader) { + this.targetClassName = targetClassName; + this.targetClassLoader = targetClassLoader; + } + + @Override + public byte[] transform(ClassLoader loader, String className, Class classBeingRedefined, + ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException { + byte[] byteCode = classfileBuffer; + + String finalTargetClassName = this.targetClassName.replaceAll("\\.", "/"); //replace . with / + if (!className.equals(finalTargetClassName)) { + return byteCode; + } + + if (className.equals(finalTargetClassName) && loader.equals(targetClassLoader)) { + LOGGER.info("[Agent] Transforming class MyAtm"); + try { + ClassPool cp = ClassPool.getDefault(); + CtClass cc = cp.get(targetClassName); + CtMethod m = cc.getDeclaredMethod(WITHDRAW_MONEY_METHOD); + m.addLocalVariable("startTime", CtClass.longType); + m.insertBefore("startTime = System.currentTimeMillis();"); + + StringBuilder endBlock = new StringBuilder(); + + m.addLocalVariable("endTime", CtClass.longType); + m.addLocalVariable("opTime", CtClass.longType); + endBlock.append("endTime = System.currentTimeMillis();"); + endBlock.append("opTime = (endTime-startTime)/1000;"); + + endBlock.append("LOGGER.info(\"[Application] Withdrawal operation completed in:\" + opTime + \" seconds!\");"); + + m.insertAfter(endBlock.toString()); + + byteCode = cc.toBytecode(); + cc.detach(); + } catch (NotFoundException | CannotCompileException | IOException e) { + LOGGER.error("Exception", e); + } + } + return byteCode; + } +} diff --git a/core-java/src/main/java/com/baeldung/instrumentation/agent/MyInstrumentationAgent.java b/core-java/src/main/java/com/baeldung/instrumentation/agent/MyInstrumentationAgent.java new file mode 100644 index 000000000000..685520276edc --- /dev/null +++ b/core-java/src/main/java/com/baeldung/instrumentation/agent/MyInstrumentationAgent.java @@ -0,0 +1,59 @@ +package com.baeldung.instrumentation.agent; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.lang.instrument.Instrumentation; + +public class MyInstrumentationAgent { + private static Logger LOGGER = LoggerFactory.getLogger(MyInstrumentationAgent.class); + + public static void premain(String agentArgs, Instrumentation inst) { + LOGGER.info("[Agent] In premain method"); + + String className = "com.baeldung.instrumentation.application.MyAtm"; + transformClass(className,inst); + } + + public static void agentmain(String agentArgs, Instrumentation inst) { + LOGGER.info("[Agent] In agentmain method"); + + String className = "com.baeldung.instrumentation.application.MyAtm"; + transformClass(className,inst); + } + + private static void transformClass(String className, Instrumentation instrumentation) { + Class targetCls = null; + ClassLoader targetClassLoader = null; + // see if we can get the class using forName + try { + targetCls = Class.forName(className); + targetClassLoader = targetCls.getClassLoader(); + transform(targetCls, targetClassLoader, instrumentation); + return; + } catch (Exception ex) { + LOGGER.error("Class [{}] not found with Class.forName"); + } + // otherwise iterate all loaded classes and find what we want + for(Class clazz: instrumentation.getAllLoadedClasses()) { + if(clazz.getName().equals(className)) { + targetCls = clazz; + targetClassLoader = targetCls.getClassLoader(); + transform(targetCls, targetClassLoader, instrumentation); + return; + } + } + throw new RuntimeException("Failed to find class [" + className + "]"); + } + + private static void transform(Class clazz, ClassLoader classLoader, Instrumentation instrumentation) { + AtmTransformer dt = new AtmTransformer(clazz.getName(), classLoader); + instrumentation.addTransformer(dt, true); + try { + instrumentation.retransformClasses(clazz); + } catch (Exception ex) { + throw new RuntimeException("Transform failed for class: [" + clazz.getName() + "]", ex); + } + } + +} diff --git a/core-java/src/main/java/com/baeldung/instrumentation/application/AgentLoader.java b/core-java/src/main/java/com/baeldung/instrumentation/application/AgentLoader.java new file mode 100644 index 000000000000..2c1cd759a5df --- /dev/null +++ b/core-java/src/main/java/com/baeldung/instrumentation/application/AgentLoader.java @@ -0,0 +1,46 @@ +package com.baeldung.instrumentation.application; + +import com.sun.tools.attach.VirtualMachine; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.File; +import java.util.Optional; + +/** + * Created by adi on 6/10/18. + */ +public class AgentLoader { + private static Logger LOGGER = LoggerFactory.getLogger(AgentLoader.class); + + public static void run(String[] args) { + String agentFilePath = "/home/adi/Desktop/agent-1.0.0-jar-with-dependencies.jar"; + String applicationName = "MyAtmApplication"; + + //iterate all jvms and get the first one that matches our application name + Optional jvmProcessOpt = Optional.ofNullable(VirtualMachine.list() + .stream() + .filter(jvm -> { + LOGGER.info("jvm:{}", jvm.displayName()); + return jvm.displayName().contains(applicationName); + }) + .findFirst().get().id()); + + if(!jvmProcessOpt.isPresent()) { + LOGGER.error("Target Application not found"); + return; + } + File agentFile = new File(agentFilePath); + try { + String jvmPid = jvmProcessOpt.get(); + LOGGER.info("Attaching to target JVM with PID: " + jvmPid); + VirtualMachine jvm = VirtualMachine.attach(jvmPid); + jvm.loadAgent(agentFile.getAbsolutePath()); + jvm.detach(); + LOGGER.info("Attached to target JVM and loaded Java agent successfully"); + } catch (Exception e) { + throw new RuntimeException(e); + } + } + +} diff --git a/core-java/src/main/java/com/baeldung/instrumentation/application/Launcher.java b/core-java/src/main/java/com/baeldung/instrumentation/application/Launcher.java new file mode 100644 index 000000000000..87e494baab17 --- /dev/null +++ b/core-java/src/main/java/com/baeldung/instrumentation/application/Launcher.java @@ -0,0 +1,14 @@ +package com.baeldung.instrumentation.application; + +/** + * Created by adi on 6/14/18. + */ +public class Launcher { + public static void main(String[] args) throws Exception { + if(args[0].equals("StartMyAtmApplication")) { + new MyAtmApplication().run(args); + } else if(args[0].equals("LoadAgent")) { + new AgentLoader().run(args); + } + } +} diff --git a/core-java/src/main/java/com/baeldung/instrumentation/application/MyAtm.java b/core-java/src/main/java/com/baeldung/instrumentation/application/MyAtm.java new file mode 100644 index 000000000000..f826e8297572 --- /dev/null +++ b/core-java/src/main/java/com/baeldung/instrumentation/application/MyAtm.java @@ -0,0 +1,19 @@ +package com.baeldung.instrumentation.application; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Created by adi on 6/11/18. + */ +public class MyAtm { + private static Logger LOGGER = LoggerFactory.getLogger(MyAtm.class); + + private static final int account = 10; + + public static void withdrawMoney(int amount) throws InterruptedException { + Thread.sleep(2000l); //processing going on here + LOGGER.info("[Application] Successful Withdrawal of [{}] units!", amount); + + } +} diff --git a/core-java/src/main/java/com/baeldung/instrumentation/application/MyAtmApplication.java b/core-java/src/main/java/com/baeldung/instrumentation/application/MyAtmApplication.java new file mode 100644 index 000000000000..425511285e32 --- /dev/null +++ b/core-java/src/main/java/com/baeldung/instrumentation/application/MyAtmApplication.java @@ -0,0 +1,19 @@ +package com.baeldung.instrumentation.application; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +public class MyAtmApplication { + + private static Logger LOGGER = LoggerFactory.getLogger(MyAtmApplication.class); + + public static void run(String[] args) throws Exception { + LOGGER.info("[Application] Starting ATM application"); + MyAtm.withdrawMoney(Integer.parseInt(args[2])); + + Thread.sleep(Long.valueOf(args[1])); + + MyAtm.withdrawMoney(Integer.parseInt(args[3])); + } + +} diff --git a/core-java/src/main/resources/META-INF/MANIFEST.MF b/core-java/src/main/resources/META-INF/MANIFEST.MF new file mode 100644 index 000000000000..988de3193dcf --- /dev/null +++ b/core-java/src/main/resources/META-INF/MANIFEST.MF @@ -0,0 +1,5 @@ +Agent-Class: com.baeldung.instrumentation.agent.MyInstrumentationAgent +Can-Redefine-Classes: true +Can-Retransform-Classes: true +Premain-Class: com.baeldung.instrumentation.agent.MyInstrumentationAgent +Main-Class: com.baeldung.instrumentation.application.Launcher diff --git a/core-java/src/main/resources/log4j2.xml b/core-java/src/main/resources/log4j2.xml new file mode 100644 index 000000000000..a824bef9b056 --- /dev/null +++ b/core-java/src/main/resources/log4j2.xml @@ -0,0 +1,13 @@ + + + + + + + + + + + + + \ No newline at end of file