How to get rid of java.lang.RuntimeException: cannot find App Engine agent in Eclipse Helios?

Question

java.lang.RuntimeException: Unable to locate the App Engine agent. Please use dev_appserver, KickStart, or set the jvm flag: "-javaagent:<sdk_root>/lib/agent/appengine-agent.jar" at com.google.appengine.tools.development.DevAppServerFactory.testAgentIsInstalled(DevAppServerFactory.java:102) at com.google.appengine.tools.development.DevAppServerFactory.createDevAppServer(DevAppServerFactory.java:77) at com.google.appengine.tools.development.DevAppServerFactory.createDevAppServer(DevAppServerFactory.java:38) at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:154) at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48) at com.google.appengine.tools.development.DevAppServerMain.<init>(DevAppServerMain.java:113) at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:89) Caused by: java.lang.NoClassDefFoundError: com/google/appengine/tools/development/agent/AppEngineDevAgent at com.google.appengine.tools.development.DevAppServerFactory.testAgentIsInstalled(DevAppServerFactory.java:98) ... 6 more Caused by: java.lang.ClassNotFoundException: com.google.appengine.tools.development.agent.AppEngineDevAgent at java.net.URLClassLoader$1.run(URLClassLoader.java:202) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:248) ... 7 more 

I searched on google and they asked to change the VM argument. These answers do not work with my eclipse. Maybe because these answers were for older versions of the eclipse. Can someone help me with this?

Thanks at Advance.

Answer 1

Go to your project properties> Java build path> edit your sdk application engine and configure it. Add the latest sdk and the problem will be solved.

Answer 2

I had to deal with this problem over and over again because my project launch configuration continued to forget the -javaagent VM option. In Eclipse, on the menu bar, select Run -> Run Configurations ... -> Web Application (blue Google-g) -> select a launch configuration that creates problems. Select the "Arguments" tab. In the VM Arguments text box, add the following entry, setting it to your unique path and unique version of the Eclipse GAE SDK:
- javaagent:C:\path-to-your-eclipse\plugins\com.google.appengine.eclipse.sdkbundle_1.6.4.v201203300216r37\appengine-java-sdk-1.6.4\lib\agent\appengine-agent.jar
Click Apply, and then try Run.

Answer 3

I did the same, only the error still didn’t go. However, you also need to remove all previously installed SDKs so that everything can work.

Answer 4

This can also happen if there are two or more Google App Engine SDK libraries in the build path. This happened to me when I included libs from my project, and also included those that were installed through Eclipse.

The best way to verify this is to go to Project Properties> Java Build Path. Make sure that only one appengine-api- * (* is a wildcard for file names). The installed Eclipse SDK is included in the App Engine SDK.

The image of what I'm talking about is below