Adding JPanel from another class to JPanel in JFrame
I can't get my JFrame from main class to display JPanel from another class. Everything compiles without errors. JFrameTest.java: package jframetest; import java.awt.FlowLayout; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; public class JFrameTest extends JFrame { public JFrameTest() { FlowLayout mainLayout = new FlowLayout(); setSize(320, 480); setResizable(false); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setLayout(mainLayout); JPanel panelMain = new JPanel(mainLayout); JButton testButton = new JButton("Test12"); panelMain.add(testButton); JPanelOne