showMessageDialog() function gives an error

[glv]

Hello,

Here is a working example that replaced frame with null:

Open console instead of window

Hello, There is always javax.swing.JOptionPane for simple IO: import javax.swing.JOptionPane; int col; void setup() { } void draw() { background(col); } void keyPressed() { thread("MessageDialog_thread"); } void MessageDialog_thread() { String strInp = JOptionPane.showInputDialog(null,"Enter a color 0 to 255:"); col = int(strInp); JOptionPane.showMessageDialog(null, col, "Output", JOptionPane.PLAIN_MESSAGE); }

Adding this to your code will also work:

    import javax.swing.JFrame;
    JFrame frame = new JFrame("JOptionPane showMessageDialog example");

Insight gleaned from here:
Java: JOptionPane showMessageDialog examples (part 1) | alvinalexander.com

:)