Google Cloud Shell Defaults to Java 11

[lazau-g]

Instructions in the top level README.md as well as in walkthroughs/week-0-setup/intro-walkthrough.md and elsewhere indicate that Google Cloud Shell is the recommended environment to go through the program.

It seems the program walkthrough uses Java 8 (as seen in all pom.xml files) - however Google Cloud Shell uses Java 11 as the default, despite documentation http://cloud/shell/docs/how-cloud-shell-works#language_support indicating otherwise. [Repro: Go to Google Cloud Shell, run 'java --version'].

Java 11 causes issues with some examples. I have found one, but there may be more

The example at walkthroughs/week-3-libraries/blobstore/examples/hello-world/ yields the following error when running under Java 11

HTTP ERROR 500
Problem accessing /_ah/upload/agw5NzkzOTYwNDM5NDJyIgsSFV9fQmxvYlVwbG9hZFNlc3Npb25fXxiAgICAgICgCQw. Reason:

    Server Error
Caused by:
java.lang.NoClassDefFoundError: javax/activation/DataSource
	at com.google.appengine.api.blobstore.dev.UploadBlobServlet.handleUpload(UploadBlobServlet.java:171)
	at com.google.appengine.api.blobstore.dev.UploadBlobServlet.access$000(UploadBlobServlet.java:69)
	at com.google.appengine.api.blobstore.dev.UploadBlobServlet$1.run(UploadBlobServlet.java:115)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at com.google.appengine.api.blobstore.dev.UploadBlobServlet.doPost(UploadBlobServlet.java:112)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:867)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1623)
	at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:134)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:48)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at com.google.appengine.tools.development.jetty9.StaticFileFilter.doFilter(StaticFileFilter.java:123)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectRequest(DevAppServerModulesFilter.java:366)
	at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectModuleRequest(DevAppServerModulesFilter.java:349)
	at com.google.appengine.tools.development.DevAppServerModulesFilter.doFilter(DevAppServerModulesFilter.java:116)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at com.google.appengine.tools.development.DevAppServerRequestLogFilter.doFilter(DevAppServerRequestLogFilter.java:44)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1602)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:540)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1588)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1345)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:480)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1557)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1247)
	at com.google.appengine.tools.development.jetty9.DevAppEngineWebAppContext.doScope(DevAppEngineWebAppContext.java:94)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at com.google.appengine.tools.development.jetty9.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:595)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at org.eclipse.jetty.server.Server.handle(Server.java:502)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:364)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:305)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126)
	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:765)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:683)
	at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.ClassNotFoundException: javax.activation.DataSource
	at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:471)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
	at com.google.appengine.tools.development.DevAppServerClassLoader.loadClass(DevAppServerClassLoader.java:108)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
	... 57 more
Caused by:
java.lang.ClassNotFoundException: javax.activation.DataSource
	at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:471)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
	at com.google.appengine.tools.development.DevAppServerClassLoader.loadClass(DevAppServerClassLoader.java:108)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
	at com.google.appengine.api.blobstore.dev.UploadBlobServlet.handleUpload(UploadBlobServlet.java:171)
	at com.google.appengine.api.blobstore.dev.UploadBlobServlet.access$000(UploadBlobServlet.java:69)
	at com.google.appengine.api.blobstore.dev.UploadBlobServlet$1.run(UploadBlobServlet.java:115)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at com.google.appengine.api.blobstore.dev.UploadBlobServlet.doPost(UploadBlobServlet.java:112)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:867)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1623)
	at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:134)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:48)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at com.google.appengine.tools.development.jetty9.StaticFileFilter.doFilter(StaticFileFilter.java:123)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectRequest(DevAppServerModulesFilter.java:366)
	at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectModuleRequest(DevAppServerModulesFilter.java:349)
	at com.google.appengine.tools.development.DevAppServerModulesFilter.doFilter(DevAppServerModulesFilter.java:116)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at com.google.appengine.tools.development.DevAppServerRequestLogFilter.doFilter(DevAppServerRequestLogFilter.java:44)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1602)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:540)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1588)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1345)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:480)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1557)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1247)
	at com.google.appengine.tools.development.jetty9.DevAppEngineWebAppContext.doScope(DevAppEngineWebAppContext.java:94)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at com.google.appengine.tools.development.jetty9.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:595)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at org.eclipse.jetty.server.Server.handle(Server.java:502)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:364)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:305)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126)
	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:765)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:683)
	at java.base/java.lang.Thread.run(Thread.java:834)
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--

Another minor issue: when following the instructions in http://cloud/shell/docs/how-cloud-shell-works#language_support to switch to Java 8 gives the following output

$ sudo update-java-alternatives -s java-1.8.0-openjdk-amd64 && export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64/jre
update-alternatives: error: no alternatives for mozilla-javaplugin.so
update-java-alternatives: plugin alternative does not exist: /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so

The output suggests that the change to Java 8 failed, but in fact it succeeded

$ java -version
openjdk version "1.8.0_252"
OpenJDK Runtime Environment (build 1.8.0_252-8u252-b09-1~deb9u1-b09)
OpenJDK 64-Bit Server VM (build 25.252-b09, mixed mode)

I realize this issue isn't entirely caused by the code/repo, but I wanted to document it so that people following along can have a reference point.

[KevinWorkman]

Hey thanks for catching this. I'm going to look into adding instructions for switching the Java version this weekend.

A more advanced solution would be to play with default configurations at the gsuite level. I don't have any experience with that though, so I'm going to focus on the low-tech solution for now.