FULL PRODUCT VERSION :
openjdk version "14-ea" 2020-03-17
OpenJDK Runtime Environment (build 14-ea+17-721)
OpenJDK 64-Bit Server VM (build 14-ea+17-721, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Mac OS X (Japanese IM activated)

A DESCRIPTION OF THE PROBLEM :
Even if Component.enableInputMethods(false) was called,
Japanese Input Method's prediction window appears.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Compile and launch the sample code
2. Turn on Native Japanese IM
3. Type some key like ,"kyo".

EXPECTED VERSUS ACTUAL BEHAVIOR :
Expected:
"kyo" input to JTextField. No other action.
Actual:
"kyo" input to JTextField, and Native IM's prediction window appears.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
import javax.swing.JTextField;

public class DisableIMTest {

public static void main(String[] args) {
    JFrame frame = new JFrame("DisableIMTest");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JTextField textField = new JTextField();
    textField.enableInputMethods(false);
    textField.addKeyListener(new KeyListener() {
        public void keyPressed(KeyEvent kev) {
            System.out.println("keyPressed: " + kev);
        }

        public void keyReleased(KeyEvent kev) {
            System.out.println("keyReleased: " + kev);
        }

        public void keyTyped(KeyEvent kev) {
            System.out.println("keyTyped: " + kev);
        }
    });
    frame.add(textField);
    frame.pack();
    frame.setSize(300,100);
    frame.setVisible(true);
}
}
---------- END SOURCE ----------