How to Write a Key Listener to Track All Keystrokes in Java

How can I write a key listener to track all keystrokes in Java?

It's possible but requires an implementation taking advantage of JNI which will not always be portable.

Java System Hook is one such library that will work with Windows 32 & 64 bit.

Capturing keystrokes in a panel in java

You need to add a new FocusListener and a new KeyListener to the panel. If you only want the keystrokes captured when the panel is in focus, get the FocusListener's action to add the KeyListener and remove it.

Capturing specific keystrokes in Java Swing

So now that I have a KeyStroke object, how do I go about checking it against a KeyEvent object in my KeyListener?

You don't use a KeyListener. Swing was designed to be used with Key Bindings.

Check out Key Bindings which contains a program to list the default bindings of each Swing component. It also give some example of how you might create your own ey Bindings. It also contains a link to the Swing tutorial on Key Bindings which explains the whole process in more detail

How can I listen for key presses (within Java Swing) across all components?

It is possible.

KeyboardFocusManager.getCurrentKeyboardFocusManager()
  .addKeyEventDispatcher(new KeyEventDispatcher() {
      @Override
      public boolean dispatchKeyEvent(KeyEvent e) {
        System.out.println("Got key event!");
        return false;
      }
});

That will grab all key events. Returning false allows the keyboard focus manager to resume normal key event dispatching to the various components.

If you want to catch key combos, you can keep a set of "pressed keys." Whenever a key is pressed, add it to the set and check what keys are already in the set. When a key is released, remove it from the set.

JavaFX key listener for multiple keys pressed implementation?

One way to tackle this problem is to create a KeyCombination object and set some of its properties to what you see below.

Try the following:

textfield.getScene().getAccelerators().put(new KeyCodeCombination(
    KeyCode.C, KeyCombination.CONTROL_ANY), new Runnable() {
    @Override public void run() {
        //Insert conditions here
        textfield.requestFocus();
    }
});