Added Change ClassFile Versions Plugin

src/main/java/the/bytecode/club/bytecodeviewer/BytecodeViewer.java

@@ -514,6 +514,16 @@ public class BytecodeViewer
     {
         BetterJOptionPane.showMessageDialog(viewer, message);
     }
+
+    /**
+     * Send a message to alert the user
+     *
+     * @param message the message you need to send
+     */
+    public static String showInput(String message)
+    {
+        return BetterJOptionPane.showInputDialog(viewer, message);
+    }
     
     /**
      * Alerts the user the program is running something in the background
@@ -561,6 +571,14 @@ public class BytecodeViewer
         new ExceptionUI(t, author);
     }
     
+    /**
+     * Refreshes the title on all of the opened tabs
+     */
+    public static void updateAllClassNodeByteArrays()
+    {
+        resourceContainers.forEach(ResourceContainer::updateClassNodeBytes);
+    }
+    
     /**
      * Refreshes the title on all of the opened tabs
      */
@@ -572,6 +590,23 @@ public class BytecodeViewer
             viewer.refreshTitle();
         }
     }
+    
+    /**
+     * Refreshes the title on all of the opened tabs
+     */
+    public static void refreshAllTabs()
+    {
+        new Thread(()->
+        {
+            updateBusyStatus(true);
+            for (int i = 0; i < BytecodeViewer.viewer.workPane.tabs.getTabCount(); i++)
+            {
+                ResourceViewer viewer = ((TabbedPane) BytecodeViewer.viewer.workPane.tabs.getTabComponentAt(i)).resource;
+                viewer.refresh(null);
+            }
+            updateBusyStatus(false);
+        }, "Refresh All Tabs").start();
+    }
 
     /**
      * Resets the workspace with optional user input required

src/main/java/the/bytecode/club/bytecodeviewer/plugin/preinstalled/ChangeClassFileVersions.java

@@ -0,0 +1,42 @@
+package the.bytecode.club.bytecodeviewer.plugin.preinstalled;
+
+import org.objectweb.asm.tree.ClassNode;
+import the.bytecode.club.bytecodeviewer.BytecodeViewer;
+import the.bytecode.club.bytecodeviewer.api.Plugin;
+import the.bytecode.club.bytecodeviewer.api.PluginConsole;
+
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+
+/**
+ * As long as there are no new opcodes or API changes you can use this plugin to downgrade compiled code
+ *
+ * 1) Import a JDK-11 (or higher) Jar resource inside of BCV
+ * 2) Run this plugin
+ * 3) Export as ZIP, then rename as Jar - Your ClassFiles will now run on JDK-8 (or whatever you selected)
+ *
+ * @author Konloch
+ * @since 07/11/2021
+ */
+public class ChangeClassFileVersions extends Plugin
+{
+    @Override
+    public void execute(ArrayList<ClassNode> classNodeList)
+    {
+        //prompt dialogue for version number
+        // TODO: include a little diagram of what JDK is which number
+        int newVersion = Integer.parseInt(BytecodeViewer.showInput("Class Version Number: (52 = JDK 8)"));
+        
+        //update the ClassFile version
+        classNodeList.forEach(classNode -> classNode.version = newVersion);
+        
+        //update the the resource byte[]
+        BytecodeViewer.updateAllClassNodeByteArrays();
+        
+        //force refresh all tabs
+        BytecodeViewer.refreshAllTabs();
+        
+        //alert the changes
+        BytecodeViewer.showMessage("Set all of the class versions to " + newVersion);
+    }
+}