Every time I try and recompile code after de-compiling, an error is given that says the following:

[ERRR:2/3/18 4:30 PM] Could not recompile, user attempted recompile from JRE process (not JDK).
[ERRR:2/3/18 4:30 PM] You cannot use this feature while running Recaf under the JRE.
Recompilation relies on Recaf being executed in a JDK.
Please re-run with a JDK.

I am currently running it with a JDK. The trace I am given is the following:

Trace:
me.coley.recaf.ui.component.panel.DecompilePanel.recompile(DecompilePanel.java:109)
me.coley.recaf.ui.component.panel.DecompilePanel.lambda$new$0(DecompilePanel.java:68)
me.coley.recaf.ui.component.action.ActionMenuItem$1.actionPerformed(ActionMenuItem.java:21)
javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
javax.swing.DefaultButtonModel.setPressed(Unknown Source)
javax.swing.AbstractButton.doClick(Unknown Source)
javax.swing.plaf.basic.BasicMenuItemUI.doClick(Unknown Source)
javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(Unknown Source)
java.awt.Component.processMouseEvent(Unknown Source)
javax.swing.JComponent.processMouseEvent(Unknown Source)
java.awt.Component.processEvent(Unknown Source)
java.awt.Container.processEvent(Unknown Source)
java.awt.Component.dispatchEventImpl(Unknown Source)
java.awt.Container.dispatchEventImpl(Unknown Source)
java.awt.Component.dispatchEvent(Unknown Source)
java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
java.awt.Container.dispatchEventImpl(Unknown Source)
java.awt.Window.dispatchEventImpl(Unknown Source)
java.awt.Component.dispatchEvent(Unknown Source)
java.awt.EventQueue.dispatchEventImpl(Unknown Source)
java.awt.EventQueue.access$500(Unknown Source)
java.awt.EventQueue$3.run(Unknown Source)
java.awt.EventQueue$3.run(Unknown Source)
java.security.AccessController.doPrivileged(Native Method)
java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
java.awt.EventQueue$4.run(Unknown Source)
java.awt.EventQueue$4.run(Unknown Source)
java.security.AccessController.doPrivileged(Native Method)
java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
java.awt.EventQueue.dispatchEvent(Unknown Source)
java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
java.awt.EventDispatchThread.pumpEvents(Unknown Source)
java.awt.EventDispatchThread.pumpEvents(Unknown Source)
java.awt.EventDispatchThread.run(Unknown Source)

Any idea as to why this is happening?

How to copy method on recaf?

Let assume I had method called setBeeperVolume and I want to copy method to setBeeperVolume2.
is it possible to do?

Thanks

It would be REALLY neat if recaf could be applied to a jvm as an agent and the edits would be applied via the instrumentation API.

It'd be sorta like JavaSnoop.

So this would probably pass some arguments to the main method, which would replace the file menu with a "refresh classes" button or something similar. It would still behave largely the same as before with the file tree, as that can just be retrieved via the class path / agent launch args.

Since it would have access to all the libraries I'd imagine there should be some sorta option to limit what is accessible so some operations of recaf aren't slowed to a halt.

Potential applications:

• Display flow (Bonus for editing, ideal would be a node-like structure)
  • Large-scale: Call mapping entire programs from main([Ljava/lang/String;) entry points
  • Small-scale: Control flow of methods
• Class relations
  • Inheritance hierarchy (Parent, interfaces, implementations)

Describe the bug
Recaf is adding the following method to any edited class when exporting
void temp();
Hence you get this error when you try to run the class
java.lang.ClassFormatError: Absent Code attribute in method that is not native or abstract in class file

Sortable-Columns:

• Num: Index in member list
• Name: If names match, sort by desc
• Desc: If descs match, sort by name
• Signature: If signatures, sort by name

This is exception thrown when saving jar(recaf is built from latest code revision 3d83c59):

NegativeArraySizeException:
Message: null
Trace:
org.objectweb.asm.Frame.merge(Frame.java:1447)
org.objectweb.asm.MethodWriter.visitMaxs(MethodWriter.java:1520)
org.objectweb.asm.tree.MethodNode.accept(MethodNode.java:835)
org.objectweb.asm.tree.MethodNode.accept(MethodNode.java:727)
org.objectweb.asm.tree.ClassNode.accept(ClassNode.java:452)
me.coley.recaf.asm.AsmUtil.toBytes(AsmUtil.java:135)
me.coley.recaf.asm.JarData.save(JarData.java:55)
me.coley.recaf.Recaf.saveFile(Recaf.java:100)
me.coley.recaf.ui.Gui$2.actionPerformed(Gui.java:90)
javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
javax.swing.AbstractButton.doClick(AbstractButton.java:376)
javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:833)
javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:877)
java.awt.Component.processMouseEvent(Component.java:6533)
javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
java.awt.Component.processEvent(Component.java:6298)
java.awt.Container.processEvent(Container.java:2236)
java.awt.Component.dispatchEventImpl(Component.java:4889)
java.awt.Container.dispatchEventImpl(Container.java:2294)
java.awt.Component.dispatchEvent(Component.java:4711)
java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
java.awt.Container.dispatchEventImpl(Container.java:2280)
java.awt.Window.dispatchEventImpl(Window.java:2746)
java.awt.Component.dispatchEvent(Component.java:4711)
java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
java.awt.EventQueue.access$500(EventQueue.java:97)
java.awt.EventQueue$3.run(EventQueue.java:709)
java.awt.EventQueue$3.run(EventQueue.java:703)
java.security.AccessController.doPrivileged(Native Method)
java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
java.awt.EventQueue$4.run(EventQueue.java:731)
java.awt.EventQueue$4.run(EventQueue.java:729)
java.security.AccessController.doPrivileged(Native Method)
java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
Cause: null

why only support .jar ?

Have a panel to the left of the list for drawing the arrows. For now, the destinations are just highlighted.

1. FilePrompt.java#L16, L34, L51 and L63
   

2. JarFileTree.java#L35, L58, L64 and L67
   

3. AccessPanel.java#L24-L27 and L45
   

4. DefinitionBox.java#L63 and L96
   
   

5. MemberTable.java#L29, VariableTable.java#L37 and ClassDisplayPanel.java#L224
   

Take this example:

class A {
    void x() { String s = "example"; }
    void x(int i) { string s = "example"; }
}

If you were to search strings for example the results would show:

• Class A
  • Method x
    • "example" <-- belongs to the first method
    • "example" <-- belongs to the second method (int i)

To Reproduce
Steps to reproduce the behavior:

1. Search for something in an obfuscated assembly where method names match but method descriptors do not
2. See results that match above

Solution

Associate results with name + description rather than just name. Showing the description is optional. Just the association matters.

Add space between labels and textfields (http://prntscr.com/grulyr) (like this http://prntscr.com/grultw)

A friend of mine has suggested adding APK support, but I'm not sure how to approach that given the major differences between standard java's bytecode and dalvik.

Any ideas / suggestions on how to approach this would be greatly appreciated.

Possible way to include: Allow for the cell selection to put extra content to a map, which the cell renderer slaps on the end of items.

The project failed to compile for me in Java 8:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.6.1:compile (default-compile) on project recaf: Compilation failure
[ERROR] /Documents/Crackmes/JavaCrackmes/recaf/Recaf/src/me/coley/recaf/asm/OpcodeUtil.java:[147,72] incompatible types: inference variable T has incompatible bounds
[ERROR] equality constraints: java.lang.String,E
[ERROR] lower bounds: java.lang.Object
[ERROR] -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.6.1:compile (default-compile) on project recaf: Compilation fai
/Documents/Crackmes/JavaCrackmes/recaf/Recaf/src/me/coley/recaf/asm/OpcodeUtil.java:[147,72] incompatible types: inference variable T has incompatible bounds
equality constraints: java.lang.String,E
lower bounds: java.lang.Object

Eclipse has a bug report that seems to address this (https://bugs.eclipse.org/bugs/show_bug.cgi?id=469297)
As the bug report suggests, Eclipse 4.6.3 did not detect this problem in the code.

Changing the code on line 147:
/**
* Empty list.
*/
public static final Set OPS_EMPTY = Stream.of("").collect(Collectors.toCollection(LinkedHashSet::new));

That allowed it to compile and Recaf seemed to work just fine. Don't know the real consequences of this change!

When showing the opcode list of a method, I oftentimes get a number of elements that are missing all text content, including the number in front. The console shows the following warning:

(java:22546): Gtk-WARNING **: Unable to locate theme engine in module_path: "adwaita",
[INFO:5/28/18 11:37 PM] Loaded input from: 'BOSEconomy_0.7.8.1.jar'
Exception in thread "JavaFX Application Thread" java.lang.IllegalArgumentException
        at org.objectweb.asm.Type.getType(Type.java:443)
        at org.objectweb.asm.Type.getReturnType(Type.java:353)
        at org.objectweb.asm.Type.getReturnType(Type.java:555)
        at me.coley.recaf.ui.FormatFactory.addMethodType(FormatFactory.java:149)
        at me.coley.recaf.ui.FormatFactory.addOpcode(FormatFactory.java:203)
        at me.coley.recaf.ui.FormatFactory.opcode(FormatFactory.java:118)
        at me.coley.recaf.ui.component.InsnListEditor$OpcodeList.createFormat(InsnListEditor.java:541)
        at me.coley.recaf.ui.component.InsnListEditor$OpcodeList.lambda$10(InsnListEditor.java:514)
        at com.sun.javafx.application.PlatformImpl.lambda$null$117(PlatformImpl.java:295)
        at java.security.AccessController.doPrivileged(Native Method)
        at com.sun.javafx.application.PlatformImpl.lambda$runLater$118(PlatformImpl.java:294)
        at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
        at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
        at com.sun.glass.ui.gtk.GtkApplication.lambda$null$450(GtkApplication.java:139)
        at java.lang.Thread.run(Thread.java:748)
[ERRR:5/28/18 11:37 PM] Could not locate: org.objectweb.asm.tree.VarInsnNode@211c7108 @1095
[ERRR:5/28/18 11:37 PM] Could not locate: org.objectweb.asm.tree.VarInsnNode@436ee718 @1100

java -version
java version "1.8.0_172"
Java(TM) SE Runtime Environment (build 1.8.0_172-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.172-b11, mixed mode)

also tried:

java -version
openjdk version "1.8.0_162"
OpenJDK Runtime Environment (build 1.8.0_162-8u162-b12-0ubuntu0.16.04.2-b12)
OpenJDK 64-Bit Server VM (build 25.162-b12, mixed mode)

Also I am on Linux Ubuntu 16 with Kubuntu-desktop installed on top of it.

ClassNotFoundExceptions thrown by CFR looking up resources are displayed when they can be ignored. The class will decompile normally regardless, it will just not be able to infer some minor things.

When inserting new opcodes, it seems the highlighted opcodes are offset by how many new opcodes there are. The issue is fixed by closing and reopening the method opcode list.

To Reproduce
Steps to reproduce the behavior:

1. Insert an opcode, like GOTO
2. Select it and notice the destinations are wrong

In this picture the highlighted lines are shifted down by one. The mark function in this case successfully identifies opcode 4 as the fail-case, and opcode 17 as the jump destination. However, the node that receives the CSS class is wrong.

When saving an unedited jar:

Currently unsure if the fault is with the input or ASM itself.

The following loop is called in Frame.merge(ClassWriter,Frame,int):

  final boolean merge(final ClassWriter cw, final Frame frame, final int edge) {
        boolean changed = false;
        int i, s, dim, kind, t;

        int nLocal = inputLocals.length;
        int nStack = inputStack.length;
        if (frame.inputLocals == null) {
            frame.inputLocals = new int[nLocal];
            changed = true;
        }

        for (i = 0; i < nLocal; ++i) {
            if (outputLocals != null && i < outputLocals.length) {
                // local and stack stuff, irrelevant for this issue
            } else {
                t = inputLocals[i];
            }
            // init
      
      // Here is the issue line
            changed |= merge(cw, t, frame.inputLocals, i);
        }
    // cut
  }

The referenced method is: Frame.merge(ClassWriter,int,int[],int)

 private static boolean merge(final ClassWriter cw, int t,
            final int[] types, final int index) {
        int u = types[index];
        if (u == t) {
            // if the types are equal, merge(u,t)=u, so there is no change
            return false;
        }
        // cut
 }

In NodeClickListener

So for fields:

• Access
• Search uses
• Default Value
• Edit Definition (This brings up menu containing)
  • Name
  • Desc
  • Signature

And methods:

• Access
• Search uses
• Local Variables
• Opcodes
• AST Flow chart
  • This is way out of my league for now
• Edit Definition (This brings up menu containing)
  • Name
  • Desc
  • Signature

So I'm currently drafting up a total redesign.

• The design / architecture is totally different, it is now primarily event-driven.
• UI is completely reworked in JavaFX (WIP, subject to change).
• Input (jar or class) is parsed as a virtual-file-system which will allow some new nifty features in the future.
• Hopefully move away from MDI (multiple inner window UI), not at this point but looking into it. (Editing methods side by side is still a goal though)

Since I'm doing things from the ground up now would be the best time to implement some wild changes (suggestions?), that were previously impossible. When these changes are done the next release will be 1.0 and will no longer be classified as a "pre-release".

Recaf should have some sort of CI to:

• Ensure every commit compiles.
• Ensure documentation is build for every commit.
• Monitor CheckStyle/FindBugs issue count for every commit.
• Make build artifacts (jarfile, docs) are available for download.

I suggets investigating Travis CI as it is free for open source projects to use.

Recaf should have unit tests to reduce the probability of regressions between releases. I suggest JUnit as it integrates nicely with Maven and is widely used.

For the original message, see the edit history, but with recent changes this has now become much easier than initially thought, so the goals have changed.

Update 6/8/2018 - Renaming things (Currently only supporting class names) updates them across the entire project.

Once PR #16 is merged, Recaf will have FindBugs and CheckStyle code-quality metrics as part of the reports in mvn site. I would propose a few things to act on these going forward:

1. Commit to "ratcheting down" the number of quality issues. I would simply record the number of issues associated with each commit and try to reduce it, or at least not increase it, with every commit.

2. Make an ongoing effort to reduce the number of quality issues, even if it's just a few at a time.

3. If necessary, disable certain checks from CheckStyle and FindBugs. Not every check will be useful for every project. That said, be sure when disabling a check project-wide that it really isn't a legitimate quality issue for this project.

4. Once the total issue count is reduced to 0, make CheckStyle and FindBugs part of mvn compile so that the build fails if any new issues appear.

I would suggest creating issues based on the content of this one, then closing this one, as this is just intended to provoke discussion/planning.

As can be seen here:

Package
├ A
├ C
├ B
├ G
├ D
├ ...
└ Z

Should be

Package
├ A
├ B
├ C
├ D
├ ...
└ Z

I get that error whenever I try to recompile a class... what do I need to do to fix this issue?

My environment variable path has the jdk properly setup... I don't know what's wrong.

OS: Windows 10, if that helps in something.

Referencing a field such as String[] array shows up as GetField String array but should show GetField String[] array

This is only an issue for non-primitives. A byte array for instance shows up correctly as [B

I tried to clone/explore/debug but you don't specify versions of libraries anywhere. I tried couple of them but they were not correct. Consider better docs or use maven/gradle for dependency management.

With 88b9bf6 I've added a half-dozen events to the plugin system, Plugins can listen to events in the me.coley.recaf.event.impl package and must inherit the me.coley.recaf.plugins.Plugin interface.

An example plugin that has overridden all the default plugin methods:

public class ExamplePlugin implements Plugin {
	@Listener
	public void onFileOpen(EFileOpen event) {
		// Called when user loads a jar file
		System.out.println("Classes: " + event.getClasses().size());
		System.out.println("Resources: " + event.getResources().size());
	}
	
	@Override
	public void init() {
		// Called when plugin is initialized.
		System.out.println("init time:" + System.currentTimeMillis());
	}

	@Override
	public void onMenuClick() {
		// Called when clicked from the UI menu
		System.out.println("clicked from UI!");
	}

	@Override
	public String getID() {
		// Optional, default returns the simplified class name.
		return "Example Plugin";
	}
}

Here are the current events categorized:

• Generic
  • On recaf initalization
  • On jar select
    • Access to contents of jar, classes & resources
  • On jar save
    • Access to contents of output (all entries as bytes)
  • On class open (Open in UI)
  • On method (opcodes) open (Open in UI)
• UI Access
  • On context-menu-create : Class window background
  • On context-menu-create : Field menu
  • On context-menu-create : Method menu
  • On context-menu-create : Method opcode menu

What additional events would you like to see? These are just a few basic ones I thought could be useful.

It should be optional for updating members in the definition window to update all references. On larger jar files this would be computationally expensive, hence the optional.

• Allow exact matches for all search types instead of defaulting to containment checks
• Regex string search
  • Disables case sensitivity option when active
• Value search (For numeric values)
• Opcode pattern matcher
  • Searches for a given sequence of opcodes
• Configurable search presets
  • Using regex as an example, presets for urls, registry keys, file paths, etc.
• Hitting return in a text box should start the search

Hey its me again! :)
tried to do an invokespecial for java/lang/IllegalArgumentException with descriptor (Ljava/lang/String)V, my mistake, it should have been (Ljava/lang/String;)V. Got this exception:

[ERRR:5/29/18 8:57 PM] ArrayIndexOutOfBoundsException: 21
org.objectweb.asm.Type.getArgumentTypes(Type.java:282)
org.objectweb.asm.Type.getArgumentTypes(Type.java:545)
me.coley.recaf.ui.FormatFactory.addMethodType(FormatFactory.java:145)
me.coley.recaf.ui.FormatFactory.addOpcode(FormatFactory.java:208)
me.coley.recaf.ui.FormatFactory.opcode(FormatFactory.java:120)
me.coley.recaf.ui.component.InsnListEditor$OpcodeList.createFormat(InsnListEditor.java:540)
me.coley.recaf.ui.component.InsnListEditor$OpcodeList.lambda$10(InsnListEditor.java:513)
com.sun.javafx.application.PlatformImpl.lambda$null$117(PlatformImpl.java:295)
java.security.AccessController.doPrivileged(Native Method)
com.sun.javafx.application.PlatformImpl.lambda$runLater$118(PlatformImpl.java:294)
com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
com.sun.glass.ui.gtk.GtkApplication.lambda$null$450(GtkApplication.java:139)
java.lang.Thread.run(Thread.java:748)

PS: Sorry for not fixing that stuff myself, kind of low on time for quality work atm ;)

Example of values for list components:

• Container:
  • Colors (By default its that gray)
  • Border type
• What should be italic / bold
• What should be given a specific color (Given as hex format)

Allow for users to skip debug/stack-frame info and such.

Due to a bug in IntelliJ's GUI designer, a certain method is created multiple times in the target JAR. In order to get rid of the duplicates, which cause the whole application JAR to crash with a java.lang.ClassFormatError, I used Recaf.

After deleting the duplicate methods in Recaf, I verified the code after decompiling it again using Recaf as well and saved the new JAR since I only saw one copy of the method left. However, the JAR did not get updated analogously to the deleted methods. All duplicates are still there. Why is that? This literally defeats the purpose of a bytecode editor when it does not edit the JAR like you did in the GUI. I'm using the as of now latest release.

Can you please fix this? Thanks a lot. I appreciate this application but it would be nice if it can deliver what it promises.

I'm trying to edit the bytecode on an older program I have. The fix just requires a change to a String constant, so the simplest solution is to edit the bytecode rather than access the git for it and go through the trouble of bringing it up to the date with the other software it relies on. I'm able to successfully change the fields I'm looking for, but unfortunately when I try to save the jar, Recaf hangs indefinitely and ends up unresponsive. If you leave your contact information, I can send you the JAR in question. Otherwise, I'm impressed with this software! It's by far one of the best bytecode editors I've used.

A highlighter synched between Decompiler and Bytecode Editor is great help.
Could you implemented ?

Thanks.

Allow user to save and load blocks of opcodes, insert anywhere. Store in relative folder and populate menu bar entry with directory tree.

Hi, i noticed that saving a jar will result in a lot of changes in *.class files which have not been touched.

I only changed a single ICONST_0 to ICONST_1 in one *.class file, and saved the jar. So i expected that this change is only reflected in the changed class. However most *.class files have been edited.

Would it be possible to add a separate Save to each single class when something has been changed? This would make it easier to compare / see what has been changed manually compared with the genuine jar

Only change in one class:

This class has not been touched manually:

Thanks.. Nice tool btw :)

It'd be nice to check if any edits made have messed up the bytecode, and to print debug information about it.

This my tester in last version
drag java file to recaf > select my class file > changes my code > save as new.jar
when i check my changes ..nothing happend and nothing changed

Area where this comes into affect: OpcodeListener:itemRemove

Removal of anything more than 100 or so opcodes hangs recaf. It is doing something but it is so slow that it may as well crash.

I really love it when a list goes:

A, B, C, E, F, D, G, I, H, ...

Examples are the opcode edit radio-buttons and dropdowns in the opcode insertion window. Ideally they should just be alphabetical.

IllegalArgumentException:
Message: null
Trace: 
org.objectweb.asm.ClassReader.<init>(ClassReader.java:185)
org.objectweb.asm.ClassReader.<init>(ClassReader.java:168)
org.objectweb.asm.ClassReader.<init>(ClassReader.java:443)
me.coley.recaf.asm.Asm.readClass(Asm.java:46)
me.coley.recaf.asm.JarData.<init>(JarData.java:58)
me.coley.recaf.Recaf.selectInput(Recaf.java:118)
me.coley.recaf.ui.SwingUI.lambda$setupMenu$0(SwingUI.java:102)
me.coley.recaf.ui.component.action.ActionMenuItem$1.actionPerformed(ActionMenuItem.java:21)
javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)

Steps-to-reproduce:

1. Click File -> Open.
2. Change File Type to All Files (or something like that, I'm not sure about the specific wording).
3. Open any file that isn't a Java program.

Maybe add some validation like this:

or

fileChooser.setAcceptAllFileFilterUsed(false);

so users will only be able to select a class or jar?

With 4207868 comes the ability to translate strings in the GUI. As an English-only speaker I would love any help creating translations.

The current lang files can be found in: https://github.com/Col-E/Recaf/tree/master/src/main/resources/lang

The format is basic JSON:

{
    "key-name": "value",
    "another-key": "value2"
}

I'm using recaf to edit target/recaf-0.9-jar-with-dependencies.jar itself, it sometimes raises exception like this ... although the application did not crash, but you might wanna look at it

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
	at com.apple.laf.AquaMenuPainter.paintMenuBarBackground(AquaMenuPainter.java:145)
	at com.apple.laf.AquaMenuBarUI.paint(AquaMenuBarUI.java:74)
	at javax.swing.plaf.ComponentUI.update(ComponentUI.java:161)
	at javax.swing.JComponent.paintComponent(JComponent.java:780)