Please help with this initial error. Thanks.

Vishal Pandya

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Feb 4, 2021, 1:02:04 AM2/4/21

to Byte Buddy

I just started with byte buddy. I get the following error for a simple agent written with Bytebuddy. I have a simple demo application which is spring boot based and trying to run it with a simple java agent code snippet below.

Appreciate a response from members. I couldn't find detailed documentation. Watched videos of the creator, but am still new to it.

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public static void premain(String agentArgs, Instrumentation inst) { System.out.println("Agent Loaded"); new AgentBuilder.Default() .with(AgentBuilder.Listener.StreamWriting.toSystemOut()) .type(hasSuperType(named("javax.sql.DataSource"))) .transform((builder, type, classLoader, module) -> builder .visit(Advice.to(VariableAdvice.class).on(isMethod()))).installOn(inst); }

-------------

import net.bytebuddy.asm.Advice;

public class VariableAdvice {

@Advice.OnMethodEnter

static void OnEnter() {

System.out.println("Hello ByteBuddy");

}

------------

"C:\Program Files\Java\jdk1.8.0_261_deleteword\bin\java.exe" - Exception in thread "main" java.lang.NoClassDefFoundError: net/bytebuddy/dynamic/DynamicType$Builder at java.lang.Class.getDeclaredMethods0(Native Method) at java.lang.Class.privateGetDeclaredMethods(Class.java:2701) at java.lang.Class.getDeclaredMethod(Class.java:2128) at sun.instrument.InstrumentationImpl.loadClassAndStartAgent(InstrumentationImpl.java:327) at sun.instrument.InstrumentationImpl.loadClassAndCallPremain(InstrumentationImpl.java:401) Caused by: java.lang.ClassNotFoundException: net.bytebuddy.dynamic.DynamicType$Builder at java.net.URLClassLoader.findClass(URLClassLoader.java:382) at java.lang.ClassLoader.loadClass(ClassLoader.java:418) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355) at java.lang.ClassLoader.loadClass(ClassLoader.java:351) ... 5 more FATAL ERROR in native method: processing of -javaagent failed

----------------------

Vishal Pandya

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Feb 4, 2021, 1:20:56 AM2/4/21

to Byte Buddy

I also tried instrumenting my demo app main class. But get the same error.

public static void premain(String agentArgs, Instrumentation inst) {
System.out.println("Agent Loaded");
new AgentBuilder.Default()
.with(AgentBuilder.Listener.StreamWriting.toSystemOut())

.type(hasSuperType(named("com.abc.DemoApplication")))

.transform((builder, type, classLoader, module) -> builder
.visit(Advice.to(VariableAdvice.class).on(isMethod()))).installOn(inst);
}

Vishal Pandya

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Feb 10, 2021, 11:09:29 AM2/10/21

to Byte Buddy

can please somebody help me? Thanks.

Rafael Winterhalter

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Feb 10, 2021, 1:44:41 PM2/10/21

to Vishal Pandya, Byte Buddy

Did you try what I suggested?

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Vishal Pandya

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Feb 11, 2021, 2:16:37 AM2/11/21

to Byte Buddy

Thank you for the response. But I am must say, you probably are refering to another thread which is not mine. Can please review my case and help? Thanks for your time. Regards.

Vishal Pandya

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Feb 11, 2021, 2:26:39 AM2/11/21

to Byte Buddy

Kindly check below link as well(just in case) where I had posted the question earlier. Thank you.

https://stackoverflow.com/questions/66034766/bytebuddy-java-agent-results-in-noclassdeffound-error

Vishal Pandya

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Feb 15, 2021, 3:59:11 AM2/15/21

to Byte Buddy

Thanks Rafael for your response. It works now. Regards.

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