Let LoadService own system-level file sourcing

This adds a simpler path for classloader-based loading of files
when we just want to get the system classloader resources shipped
with JRuby. This will reduce the chance of someone using an
improper classloader (e.g. JRubyLibrary might have loaded the wrong
file from a JRubyClassLoader rather than the one shipped with
JRuby) or stumbling on to a null classloader (as sometimes happened
to the loads from javasupport.Java when running in a bootstrap
classloader).

Author: headius

core/src/main/java/org/jruby/Ruby.java

@@ -1587,7 +1587,7 @@ public JavaSupport loadJavaSupport() {
     }
 
     private void loadBundler() {
-        loadService.loadFromClassLoader(getClassLoader(), "jruby/bundler/startup.rb", false);
+        loadService.loadFromClassLoader("jruby/bundler/startup.rb", false);
     }
 
     @SuppressWarnings("ReturnValueIgnored")
@@ -1781,15 +1781,15 @@ private void initJavaSupport(ThreadContext context) {
 
     private void initRubyKernel() {
         // load Ruby parts of core
-        loadService.loadFromClassLoader(getClassLoader(), "jruby/kernel.rb", false);
+        loadService.loadFromClassLoader("jruby/kernel.rb", false);
     }
 
     private void initRubyPreludes() {
         // We cannot load any .rb and debug new parser features
         if (RubyInstanceConfig.DEBUG_PARSER) return;
 
         // load Ruby parts of core
-        loadService.loadFromClassLoader(getClassLoader(), "jruby/preludes.rb", false);
+        loadService.loadFromClassLoader("jruby/preludes.rb", false);
     }
 
     public IRManager getIRManager() {

core/src/main/java/org/jruby/ext/bigdecimal/BigDecimalLibrary.java

@@ -43,6 +43,6 @@ public void load(Ruby runtime, boolean wrap) throws IOException {
         RubyBigDecimal.createBigDecimal(context);
 
         // using load since this file does not exist in MRI
-        loadService(context).loadFromClassLoader(Ruby.getClassLoader(), "jruby/bigdecimal.rb", false);
+        loadService(context).loadFromClassLoader("jruby/bigdecimal.rb", false);
     }
 }// BigDecimalLibrary

core/src/main/java/org/jruby/ext/jruby/JRubyLibrary.java

@@ -77,7 +77,7 @@ public void load(Ruby runtime, boolean wrap) {
         var Object = objectClass(context);
 
         // load Ruby parts of the 'jruby' library
-        loadService(context).loadFromClassLoader(runtime.getJRubyClassLoader(), "jruby/jruby.rb", false);
+        loadService(context).loadFromClassLoader("jruby/jruby.rb", false);
 
         var JRuby = defineModule(context, "JRuby").
                 defineMethods(context, JRubyLibrary.class).defineMethods(context, JRubyUtilLibrary.class);

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

@@ -139,7 +139,7 @@ public void load(Ruby runtime, boolean wrap) {
         RubyClass objectClass = (RubyClass) getProxyClass(context, java.lang.Object.class);
 
         // load Ruby parts of the 'java' library
-        loadService(context).loadFromClassLoader(Ruby.getClassLoader(), "jruby/java.rb", false);
+        loadService(context).loadFromClassLoader("jruby/java.rb", false);
 
         // rewire ArrayJavaProxy superclass to point at Object, so it inherits Object behaviors
         Access.getClass(context, "ArrayJavaProxy").

core/src/main/java/org/jruby/runtime/load/LoadService.java

@@ -186,13 +186,15 @@ public String[] getSuffixes() {
     protected final Map<String, JarFile> jarFiles = new HashMap<>(0);
 
     protected final Ruby runtime;
+    protected final ClassLoader systemClassLoader;
     protected LibrarySearcher librarySearcher;
 
     protected String mainScript;
     protected String mainScriptPath;
 
     public LoadService(Ruby runtime) {
         this.runtime = runtime;
+        this.systemClassLoader = Ruby.getClassLoader();
         if (RubyInstanceConfig.DEBUG_LOAD_TIMINGS) {
             loadTimer = new TracingLoadTimer();
         } else {
@@ -383,6 +385,10 @@ public void load(String file, boolean wrap) {
         }
     }
 
+    public void loadFromClassLoader(String file, boolean wrap) {
+        loadFromClassLoader(systemClassLoader, file, wrap);
+    }
+
     public void loadFromClassLoader(ClassLoader classLoader, String file, boolean wrap) {
         long startTime = loadTimer.startLoad("classloader:" + file);
         int currentLine = runtime.getCurrentLine();