fix: Cannot list multi-module projects properly (#450)

Author: jdneo

jdtls.ext/com.microsoft.jdtls.ext.core/.classpath

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-11"/>
 	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
 	<classpathentry kind="src" path="src/"/>
 	<classpathentry exported="true" kind="lib" path="lib/commons-io-2.5.jar"/>

jdtls.ext/com.microsoft.jdtls.ext.core/src/com/microsoft/jdtls/ext/core/PackageCommand.java

@@ -610,7 +610,8 @@ public static IJavaProject getJavaProject(String projectUri) {
         }
 
         // For multi-module scenario, findContainersForLocationURI API may return a container array,
-        // need put the result from the nearest project in front.
+        // need filter out non-Java project and put the result from the nearest project in front.
+        containers = Arrays.stream(containers).filter(c -> ProjectUtils.isJavaProject(c.getProject())).toArray(IContainer[]::new);
         Arrays.sort(containers, (Comparator<IContainer>) (IContainer a, IContainer b) -> {
             return a.getFullPath().toPortableString().length() - b.getFullPath().toPortableString().length();
         });