Add support for OpenJDK and Java 11.

Squash port of sampottinger:java11 on processing train with a number of sub-changes, resolving processing/processing#5750 in the processing4 train. Original message below.

Moves to OpenJDK11 as part of #5750. There's lots in here so a quick rundown of the bigger stuff...

**Primary required changes:**
Some changes directly support OpenJFX / OpenJDK 11:

 - Response to image loading changes caused by [JEP 320](https://openjdk.java.net/jeps/320)
 - Use of jmodules as necessitated by [JEP 261](https://openjdk.java.net/jeps/261)
 - Reponse to largely changed file paths caused by [JEP 220](https://openjdk.java.net/jeps/220).
 - Modifications in build system related to AdoptOpenJDK and Java 11 which have a different naming structure for downloads.
 - Allowing use of non-Oracle Java within internal Processing checks.

**Secondary required changes:**
There were some secondary required changes that impacted the usability of Processing after having moved to OpenJFX / OpenJDK 11:

 - Removal of com.apple.eawt calls related to [JEP 272](http://openjdk.java.net/jeps/272)
 - Response to HiDPI support on Windows and Linux in [JEP 263](https://openjdk.java.net/jeps/263)
- Removal of `java.ext.dirs`. Would be forced by [JEP 220](http://openjdk.java.net/jeps/220).
 - Due to bugs on Windows, updated the JNA jars.
 - Changes in downloader build tasks to support AdoptOpenJDK and OpenJFX.
 - Updated org.eclipse.* / equinox jars.
 - Some optimization around size of distribution.
 - Update of AppBundler.
 - Some changes in formulation of classpath and modifications in PreprocessingService given [JEP 261](https://openjdk.java.net/jeps/261).

**Incidental changes:**
This was (ahem) a bit of a larger PR with the above modifications. So, I wanted to introduce automated tests when possible and convenient along with a few changes for platform sustainability in order to support development:

 - Addition of cross-building capability (!) made possible by AdoptOpenJDK.
 - Addition of mockito for testing.
 - Upgrade of junit.
 - Addition of ant-contrib.
 - Standardized nomenclature around JRE / JDK in `build/build.xml`
 - Deduplication of code in `jre/build.xml`.
 - Addition of JavaDoc in a few places.
 - Some refactoring of PImage / Shape to support increased testing and readability in image manipulation code.

.classpath

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="lib" path="library/jogl-all.jar"/>
+	<classpathentry kind="lib" path="library/gluegen-rt.jar"/>
+	<classpathentry kind="lib" path="apple.jar"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.USER_LIBRARY/JavaFX11"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

.gitignore

@@ -1,5 +1,6 @@
 .DS_Store
 .AppleDouble
+*.iml
 ._*
 *~
 /build/shared/reference.zip

app/build.xml

@@ -13,14 +13,14 @@
     <fail unless="core-built" message="Please build the core library first and make sure it is located at ../core/library/core.jar" />
 
     <mkdir dir="bin" />
-    
+
     <!-- copy languages files -->
     <copy todir="bin">
       <fileset dir="src">
         <include name="processing/app/languages/*.properties" />
       </fileset>
     </copy>
-    
+
     <!-- in some cases, pde.jar was not getting built
 	 https://github.com/processing/processing/issues/1792 -->
     <delete file="pde.jar" />
@@ -30,22 +30,19 @@
 
     <javac source="1.8"
 	   target="1.8"
-	   destdir="bin" 
-	   excludes="**/tools/format/**" 
-	   encoding="UTF-8" 
-	   includeAntRuntime="false" 
-	   classpath="../core/library/core.jar; 
-                      ../core/apple.jar; 
-                      lib/ant.jar; 
-                      lib/ant-launcher.jar; 
+	   destdir="bin"
+	   excludes="**/tools/format/**"
+	   encoding="UTF-8"
+	   includeAntRuntime="false"
+	   classpath="../core/library/core.jar;
+                      ../core/apple.jar;
+                      lib/ant.jar;
+                      lib/ant-launcher.jar;
                       lib/jna.jar;
                       lib/jna-platform.jar"
 	   debug="on"
-	   nowarn="true"
-	   compiler="org.eclipse.jdt.core.JDTCompilerAdapter">
+	   nowarn="true">
       <src path="src" />
-      <compilerclasspath path="../java/mode/org.eclipse.jdt.core.jar; 
-                               ../java/mode/jdtCompilerAdapter.jar" />
     </javac>
   </target>
 

app/src/processing/app/Platform.java

@@ -339,10 +339,10 @@ static public File getJavaHome() {
       File[] plugins = getContentFile("../PlugIns").listFiles(new FilenameFilter() {
         public boolean accept(File dir, String name) {
           return dir.isDirectory() &&
-            name.endsWith(".jdk") && !name.startsWith(".");
+            name.contains("jdk") && !name.startsWith(".");
         }
       });
-      return new File(plugins[0], "Contents/Home/jre");
+      return new File(plugins[0], "Contents/Home");
     }
     // On all other platforms, it's the 'java' folder adjacent to Processing
     return getContentFile("java");
@@ -412,4 +412,4 @@ static public int unsetenv(String variable) {
   static public int getSystemDPI() {
     return inst.getSystemDPI();
   }
-}
+}

app/src/processing/app/platform/LinuxPlatform.java

@@ -40,20 +40,6 @@ public class LinuxPlatform extends DefaultPlatform {
   public void initBase(Base base) {
     super.initBase(base);
 
-    String javaVendor = System.getProperty("java.vendor");
-    String javaVM = System.getProperty("java.vm.name");
-    if (javaVendor == null ||
-        (!javaVendor.contains("Sun") && !javaVendor.contains("Oracle")) ||
-        javaVM == null || !javaVM.contains("Java")) {
-      Messages.showWarning("Not fond of this Java VM",
-                           "Processing requires Java 8 from Oracle.\n" +
-                           "Other versions such as OpenJDK, IcedTea,\n" +
-                           "and GCJ are strongly discouraged. Among other things, you're\n" +
-                           "likely to run into problems with sketch window size and\n" +
-                           "placement. For more background, please read the wiki:\n" +
-                           "https://github.com/processing/processing/wiki/Supported-Platforms#linux", null);
-    }
-
     // Set x11 WM_CLASS property which is used as the application
     // name by Gnome3 and other window managers.
     // https://github.com/processing/processing/issues/2534

app/src/processing/app/platform/ThinkDifferent.java

@@ -24,11 +24,15 @@
 
 import java.awt.event.*;
 import java.io.File;
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+import java.util.List;
 
 import javax.swing.*;
 
-import com.apple.eawt.*;
-import com.apple.eawt.AppEvent.*;
+import com.apple.eawt.Application;
 
 import processing.app.*;
 import processing.app.ui.About;
@@ -65,44 +69,40 @@ static protected void init(final Base base) {
     if (adapter == null) {
       adapter = new ThinkDifferent();  //base);
     }
-
-    application.setAboutHandler(new AboutHandler() {
-      public void handleAbout(AboutEvent ae) {
-        new About(null);
-      }
+
+    setHandler(application, "setAboutHandler", (proxy, method, args) -> {
+      new About(null);
+      return null;
     });
-
-    application.setPreferencesHandler(new PreferencesHandler() {
-      public void handlePreferences(PreferencesEvent arg0) {
-        base.handlePrefs();
-      }
+
+    setHandler(application, "setPreferencesHandler", (proxy, method, args) -> {
+      base.handlePrefs();
+      return null;
     });
 
-    application.setOpenFileHandler(new OpenFilesHandler() {
-      public void openFiles(OpenFilesEvent event) {
-        for (File file : event.getFiles()) {
-          base.handleOpen(file.getAbsolutePath());
-        }
+    setHandler(application, "setOpenFileHandler", (proxy, method, args) -> {
+      Method m = args[0].getClass().getMethod("getFiles");
+      for (File file : (List<File>) m.invoke(args[0])) {
+        base.handleOpen(file.getAbsolutePath());
       }
+      return null;
     });
-
-    application.setPrintFileHandler(new PrintFilesHandler() {
-      public void printFiles(PrintFilesEvent event) {
-        // TODO not yet implemented
-      }
+
+    setHandler(application, "setPrintFileHandler", (proxy, method, args) -> {
+      // TODO not yet implemented
+      return null;
     });
-
-    application.setQuitHandler(new QuitHandler() {
-      public void handleQuitRequestWith(QuitEvent event, QuitResponse response) {
-        if (base.handleQuit()) {
-          response.performQuit();
-        } else {
-          response.cancelQuit();
-        }
+
+    setHandler(application, "setQuitHandler", (proxy, method, args) -> {
+      if (base.handleQuit()) {
+        args[1].getClass().getMethod("performQuit").invoke(args[1]);
+      } else {
+        args[1].getClass().getMethod("cancelQuit").invoke(args[1]);
       }
+      return null;
     });
 
-    // Set the menubar to be used when nothing else is open. 
+    // Set the menubar to be used when nothing else is open.
     JMenuBar defaultMenuBar = new JMenuBar();
     JMenu fileMenu = buildFileMenu(base);
     defaultMenuBar.add(fileMenu);
@@ -117,12 +117,12 @@ public void handleQuitRequestWith(QuitEvent event, QuitResponse response) {
       e.printStackTrace();  // oh well, never mind
     }
 //    } else {
-//      // The douchebags at Oracle didn't feel that a working f*king menubar 
-//      // on OS X was important enough to make it into the 7u40 release. 
+//      // The douchebags at Oracle didn't feel that a working f*king menubar
+//      // on OS X was important enough to make it into the 7u40 release.
 //      //http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8007267
 //      // It languished in the JDK 8 source and has been backported for 7u60:
 //      //http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8022667
-//      
+//
 //      JFrame offscreen = new JFrame();
 //      offscreen.setUndecorated(true);
 //      offscreen.setJMenuBar(defaultMenuBar);
@@ -131,12 +131,51 @@ public void handleQuitRequestWith(QuitEvent event, QuitResponse response) {
 //      offscreen.setVisible(true);
 //    }
   }
-  
+
 
 //  public ThinkDifferent(Base base) {
 //    this.base = base;
 //  }
 
+  /**
+   * Sets a handler on an instance of {@link Application}, taking into account JVM version
+   * differences.
+   *
+   * @param app an instance of {@link Application}
+   * @param name the "set handler" method name
+   * @param handler the handler
+   */
+  private static void setHandler(Application app, String name, InvocationHandler handler) {
+    // Determine which version of com.apple.eawt.Application to use and pass it a handler of the
+    // appropriate type
+    Method[] methods = app.getClass().getMethods();
+    for (Method m : methods) {
+      if (!name.equals(m.getName())) {
+        continue;
+      }
+      if (m.getParameterCount() != 1) {
+        continue;
+      }
+      Class paramType = m.getParameterTypes()[0];
+      try {
+        // Allow a null handler
+        Object proxy = null;
+        if (handler != null) {
+          proxy = Proxy.newProxyInstance(
+              paramType.getClassLoader(), new Class<?>[] { paramType }, handler);
+        }
+        m.invoke(app, proxy);
+      } catch (IllegalArgumentException ex) {
+        // TODO: Print error?: method doesn't take an interface, etc.
+      } catch (IllegalAccessException ex) {
+        // TODO: Print error?: Other method invocation problem
+      } catch (InvocationTargetException ex) {
+        ex.getCause().printStackTrace();
+        // TODO: Print ex.getCause() a different way?
+      }
+      break;
+    }
+  }
 
   /**
    * Gimpy file menu to be used on OS X when no sketches are open.
@@ -162,7 +201,7 @@ public void actionPerformed(ActionEvent e) {
     fileMenu.add(item);
 
     item = Toolkit.newJMenuItemShift(Language.text("menu.file.sketchbook"), 'K');
-    item.addActionListener(new ActionListener() {      
+    item.addActionListener(new ActionListener() {
       @Override
       public void actionPerformed(ActionEvent e) {
         base.getNextMode().showSketchbookFrame();

app/src/processing/app/platform/WindowsPlatform.java

@@ -64,10 +64,16 @@ public class WindowsPlatform extends DefaultPlatform {
     "\\" + APP_NAME.toLowerCase() + ".exe \"%1\"";
   static final String REG_DOC = APP_NAME + ".Document";
 
+  // Starting with Java 9, the scaling is done automatically. If DPI is
+  // used to scaling within the application, one ends up with 2x the
+  // expected scale. See JEP 263.
+  private static final int WINDOWS_NATIVE_DPI = 96;
 
   public void initBase(Base base) {
     super.initBase(base);
+
     checkAssociations();
+
     //checkQuickTime();
     checkPath();
 
@@ -627,56 +633,9 @@ public int unsetenv(String variable) {
   // . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
 
 
-  // Need to extend com.sun.jna.platform.win32.User32 to access
-  // Win32 function GetDpiForSystem()
-  interface ExtUser32 extends StdCallLibrary, com.sun.jna.platform.win32.User32 {
-    ExtUser32 INSTANCE = (ExtUser32) Native.loadLibrary("user32", ExtUser32.class, W32APIOptions.DEFAULT_OPTIONS);
-
-    public int GetDpiForSystem();
-
-    public int SetProcessDpiAwareness(int value);
-
-    public final int DPI_AWARENESS_INVALID = -1;
-    public final int DPI_AWARENESS_UNAWARE = 0;
-    public final int DPI_AWARENESS_SYSTEM_AWARE = 1;
-    public final int DPI_AWARENESS_PER_MONITOR_AWARE = 2;
-
-    public Pointer SetThreadDpiAwarenessContext(Pointer dpiContext);
-
-    public final Pointer DPI_AWARENESS_CONTEXT_UNAWARE = new Pointer(-1);
-    public final Pointer DPI_AWARENESS_CONTEXT_SYSTEM_AWARE = new Pointer(-2);
-    public final Pointer DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE = new Pointer(-3);
-  }
-
-
-  static private int detected = detectSystemDPI();
-
-
   public int getSystemDPI() {
-    if (detected == -1) {
-      return super.getSystemDPI();
-    }
-    return detected;
+    // Note that this is supported "natively" within Java - See JEP 263.
+    return WINDOWS_NATIVE_DPI;
   }
 
-
-  public static int detectSystemDPI() {
-    try {
-      ExtUser32.INSTANCE.SetProcessDpiAwareness(ExtUser32.DPI_AWARENESS_SYSTEM_AWARE);
-    } catch (Throwable e) {
-      // Ignore error
-    }
-    try {
-      ExtUser32.INSTANCE.SetThreadDpiAwarenessContext(ExtUser32.DPI_AWARENESS_CONTEXT_SYSTEM_AWARE);
-    } catch (Throwable e) {
-      // Ignore error (call valid only on Windows 10)
-    }
-    try {
-      return ExtUser32.INSTANCE.GetDpiForSystem();
-    } catch (Throwable e) {
-      // DPI detection failed, fall back with default
-      System.out.println("DPI detection failed, fallback to 96 dpi");
-      return -1;
-    }
-  }
 }