Add readme section for common problems / resolutions

[thomasmodeneis]

Problem: Building Gatling 2.2.3 with JDK 7:

Jan 25, 2017 11:37:10 AM org.sonatype.guice.bean.reflect.Logs$JULSink warn
WARNING: Error injecting: io.gatling.mojo.GatlingMojo
java.lang.TypeNotPresentException: Type io.gatling.mojo.GatlingMojo not present
	at org.sonatype.guice.bean.reflect.URLClassSpace.loadClass(URLClassSpace.java:109)
	at org.sonatype.guice.bean.reflect.NamedClass.load(NamedClass.java:45)
	at org.sonatype.guice.bean.reflect.AbstractDeferredClass.get(AbstractDeferredClass.java:45)
	at com.google.inject.internal.ProviderInternalFactory.provision(ProviderInternalFactory.java:84)
	at com.google.inject.internal.InternalFactoryToInitializableAdapter.provision(InternalFactoryToInitializableAdapter.java:52)
	at com.google.inject.internal.ProviderInternalFactory$1.call(ProviderInternalFactory.java:70)
	at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:100)
	at org.sonatype.guice.plexus.lifecycles.PlexusLifecycleManager.onProvision(PlexusLifecycleManager.java:138)
	at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:108)
	at com.google.inject.internal.ProvisionListenerStackCallback.provision(ProvisionListenerStackCallback.java:55)
	at com.google.inject.internal.ProviderInternalFactory.circularGet(ProviderInternalFactory.java:68)
	at com.google.inject.internal.InternalFactoryToInitializableAdapter.get(InternalFactoryToInitializableAdapter.java:45)
	at com.google.inject.internal.InjectorImpl$3$1.call(InjectorImpl.java:965)
	at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1011)
	at com.google.inject.internal.InjectorImpl$3.get(InjectorImpl.java:961)
	at com.google.inject.Scopes$1$1.get(Scopes.java:59)
	at org.sonatype.guice.bean.locators.LazyBeanEntry.getValue(LazyBeanEntry.java:83)
	at org.sonatype.guice.plexus.locators.LazyPlexusBean.getValue(LazyPlexusBean.java:49)
	at org.codehaus.plexus.DefaultPlexusContainer.lookup(DefaultPlexusContainer.java:253)
	at org.codehaus.plexus.DefaultPlexusContainer.lookup(DefaultPlexusContainer.java:245)
	at org.apache.maven.plugin.internal.DefaultMavenPluginManager.getConfiguredMojo(DefaultMavenPluginManager.java:455)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:92)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
	at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
	at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
	at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
	at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
	at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
	at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
	at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
	at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
Caused by: java.lang.UnsupportedClassVersionError: io/gatling/mojo/GatlingMojo : Unsupported major.minor version 52.0
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
	at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClassFromSelf(ClassRealm.java:386)
	at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:42)
	at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:244)
	at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
	at org.sonatype.guice.bean.reflect.URLClassSpace.loadClass(URLClassSpace.java:101)
	... 41 more

[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1:40.619s
[INFO] Finished at: Wed Jan 25 11:37:10 CET 2017
[INFO] Final Memory: 9M/79M
[INFO] ------------------------------------------------------------------------

Solution: Use JDK 8 for build.

[thomasmodeneis]

Jenkins may fail with java.lang.OutOfMemoryError: PermGen space

WARNING: 
javax.servlet.ServletException: org.apache.commons.jelly.JellyTagException: jar:file:/var/cache/jenkins/war/WEB-INF/lib/jenkins-core-2.32.1.jar!/lib/layout/layout.jelly:83:72: <st:include> java.lang.OutOfMemoryError: PermGen space
	at org.kohsuke.stapler.jelly.JellyFacet$1.dispatch(JellyFacet.java:103)
	at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:649)
	at hudson.init.impl.InstallUncaughtExceptionHandler$1.reportException(InstallUncaughtExceptionHandler.java:30)
	at org.kohsuke.stapler.compression.CompressionFilter.reportException(CompressionFilter.java:77)
	at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:55)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:82)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:553)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
	at org.eclipse.jetty.server.Server.handle(Server.java:499)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:311)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:257)
	at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:544)
	at winstone.BoundedExecutorService$1.run(BoundedExecutorService.java:77)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:745)

Solution:
If you have a Freestyle project with a "Invoke Top Level Maven Targets" build step, you can add the appropriate JVM switches for a given build by clicking the Advanced button on the build step and entering the JVM arguments in the JVM Options field.

Alternatively, you can affect all free style Maven build steps by adding a MAVEN_OPTS global environment variable in the Jenkins global configuration. To do this, click Manage Jenkins, then Configure System. In the Global properties section, click the Environment Variables checkbox, then add a new environment variable called MAVEN_OPTS with the value set appropriately:

https://wiki.jenkins-ci.org/display/JENKINS/Builds+failing+with+OutOfMemoryErrors