WADL example fix

[senivam]

No description provided.

[senivam]

Since JDK 13+ the javadoc tool returns error:

Exit code: 4
Note: Doclet using locale: en_US
error: fatal error encountered: java.lang.AssertionError
error: Please file a bug against the javadoc tool via the Java bug reporting page
  (https://bugreport.java.com) after checking the Bug Database (https://bugs.java.com)
  for duplicates. Include error messages and the following diagnostic in your report. Thank you.
java.lang.AssertionError
	at jdk.compiler/com.sun.tools.javac.util.Assert.error(Assert.java:155)
	at jdk.compiler/com.sun.tools.javac.util.Assert.checkNonNull(Assert.java:62)
	at jdk.compiler/com.sun.tools.javac.comp.Modules.allModules(Modules.java:1222)
	at jdk.javadoc/jdk.javadoc.internal.tool.ElementsTable.findModuleOfPackageName(ElementsTable.java:855)
	at jdk.javadoc/jdk.javadoc.internal.tool.ElementsTable.addPackagesFromLocations(ElementsTable.java:535)
	at jdk.javadoc/jdk.javadoc.internal.tool.ElementsTable.computeSubpackages(ElementsTable.java:508)
	at jdk.javadoc/jdk.javadoc.internal.tool.ElementsTable.computeSpecifiedPackages(ElementsTable.java:745)
	at jdk.javadoc/jdk.javadoc.internal.tool.ElementsTable.analyze(ElementsTable.java:345)
	at jdk.javadoc/jdk.javadoc.internal.tool.JavadocTool.getEnvironment(JavadocTool.java:215)
	at jdk.javadoc/jdk.javadoc.internal.tool.Start.parseAndExecute(Start.java:565)
	at jdk.javadoc/jdk.javadoc.internal.tool.Start.begin(Start.java:398)
	at jdk.javadoc/jdk.javadoc.internal.tool.Start.begin(Start.java:347)
	at jdk.javadoc/jdk.javadoc.internal.tool.Main.execute(Main.java:57)
	at jdk.javadoc/jdk.javadoc.internal.tool.Main.main(Main.java:46)

This is documented in the JDK bug JDK-8239575

In the same bug, there is a description of some workaround however it does not seem applicable for the doclet case.

[jansupol]

The JDK bug says it is fixed in 15...

[senivam]

so, in JDK 21 it appears to be still broken, I was trying using JDK 21 and it gives listed above error

JDK 17 - same error