Only set up Java:: constants when accessed directly

Previously whenever we see a new type of Java object, we both set
up the proxy class AND set the constant. If that object's class
is not from the typical Java integration classloader hierarchy, it
will pollute the Java:: module with a normally inaccessible entry.

This change only sets up the constant when it is accessed through
the normal package reference, rather than when first seen.

Fixes jruby#8156

core/src/main/java/org/jruby/javasupport/Java.java

@@ -414,9 +414,14 @@ public static RubyModule getProxyClass(Ruby runtime, JavaClass javaClass) {
 
     @SuppressWarnings("deprecation")
     public static RubyModule getProxyClass(final Ruby runtime, final Class<?> clazz) {
+        return getProxyClass(runtime, clazz, false);
+    }
+
+    @SuppressWarnings("deprecation")
+    public static RubyModule getProxyClass(final Ruby runtime, final Class<?> clazz, boolean setConstant) {
         RubyModule proxy = runtime.getJavaSupport().getUnfinishedProxy(clazz);
         if (proxy != null) return proxy;
-        return runtime.getJavaSupport().getProxyClassFromCache(clazz);
+        return runtime.getJavaSupport().getProxyClassFromCache(clazz, setConstant);
     }
 
     // expected to handle Java proxy (Ruby) sub-classes as well
@@ -473,7 +478,6 @@ private static void generateInterfaceProxy(final Ruby runtime, final Class javaC
             proxy.includeModule(extModule);
         }
         Initializer.setupProxyModule(runtime, javaClass, proxy);
-        addToJavaPackageModule(proxy);
     }
 
     private static void generateClassProxy(Ruby runtime, Class<?> clazz, RubyClass proxy, RubyClass superClass) {
@@ -495,7 +499,6 @@ else if ( clazz == Object.class ) {
             } else {
                 proxy.getMetaClass().defineAnnotatedMethods(OldStyleExtensionInherited.class);
             }
-            addToJavaPackageModule(proxy);
         }
         else {
             createProxyClass(runtime, proxy, clazz, superClass, false);
@@ -504,9 +507,6 @@ else if ( clazz == Object.class ) {
             for ( int i = interfaces.length; --i >= 0; ) {
                 proxy.includeModule(getInterfaceModule(runtime, interfaces[i]));
             }
-            if ( Modifier.isPublic(clazz.getModifiers()) ) {
-                addToJavaPackageModule(proxy);
-            }
         }
 
         // JRUBY-1000, fail early when attempting to subclass a final Java class;
@@ -824,9 +824,7 @@ private static <T extends ParameterTypes> T checkCallableForArity(final int arit
 
     // package scheme 2: separate module for each full package name, constructed
     // from the camel-cased package segments: Java::JavaLang::Object,
-    private static void addToJavaPackageModule(RubyModule proxyClass) {
-        final Ruby runtime = proxyClass.getRuntime();
-        final Class<?> clazz = (Class<?>)proxyClass.dataGetStruct();
+    static void addToJavaPackageModule(Ruby runtime, Class<?> clazz, RubyModule proxyClass) {
         final String fullName;
         if ( ( fullName = clazz.getName() ) == null ) return;
 
@@ -1074,7 +1072,7 @@ private static RubyModule getProxyClassOrNull(final Ruby runtime, final String c
         } catch (ClassNotFoundException ex) { // used to catch NoClassDefFoundError for whatever reason
             return null;
         }
-        return getProxyClass(runtime, clazz);
+        return getProxyClass(runtime, clazz, true);
     }
 
     private static int mapMajorMinorClassVersionToJavaVersion(String msg, final int offset) {

core/src/main/java/org/jruby/javasupport/JavaPackage.java

@@ -189,7 +189,7 @@ private RubyModule relativeJavaClassOrPackage(final ThreadContext context,
 
     RubyModule relativeJavaProxyClass(final Ruby runtime, final IRubyObject name) {
         final String fullName = packageRelativeName( name.toString() ).toString();
-        return Java.getProxyClass(runtime, Java.getJavaClass(runtime, fullName));
+        return Java.getProxyClass(runtime, Java.getJavaClass(runtime, fullName), true);
     }
 
     @JRubyMethod(name = "respond_to?")

core/src/main/java/org/jruby/javasupport/JavaSupport.java

@@ -50,6 +50,7 @@
 import org.jruby.util.collections.ClassValueCalculator;
 
 import java.lang.reflect.Member;
+import java.lang.reflect.Modifier;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
@@ -369,8 +370,16 @@ final RubyModule getUnfinishedProxy(Class clazz) {
         return null;
     }
 
-    RubyModule getProxyClassFromCache(Class clazz) {
-        return proxyClassCache.get(clazz);
+    RubyModule getProxyClassFromCache(Class clazz, boolean setConstant) {
+        RubyModule proxy = proxyClassCache.get(clazz);
+
+        if (setConstant) {
+            if ( Modifier.isPublic(clazz.getModifiers()) ) {
+                Java.addToJavaPackageModule(runtime, clazz, proxy);
+            }
+        }
+
+        return proxy;
     }
 
 }