GCJ and Swing

Tue Aug 24 07:18:00 GMT 2004

Am Dienstag, 24. August 2004 08:58 schrieb Ivan Ivanov:
> --- Michael Koch <konqueror@gmx.de> wrote:
> > Huh ? Either you forgot to to specify -lgcj or you
> > should use gcj to
> > link your app.
> >
> > Michael
>> Michael,
> I am obviuosly doing something wrong. I cut my long
> class to a short sample which I am trying to compile
> and run. The class is the following
>> import javax.swing.JDialog;
> import javax.swing.JLabel;
>> public class LabelDialog {
>> public static void main(String[] args) {
> 	JDialog dialog = new JDialog(new JFrame());
> 	dialog.setTitle("Dialog with a label");
> 	JLabel label = new JLabel("The label that will be put
> in the dialog");
> 	dialog.getContentPane().add(label);
> 	dialog.pack();
> 	dialog.setVisible(true);
> }
> }
>> I am trying to compile it with
> gcj LabelDialog.java
> the following error is outputed
>> /usr/lib/gcc-lib/i386-redhat-linux/3.3.3/../../../crt1.o(.text+0x18
>):
>> In function `_start':
> : undefined reference to `main'
>> collect2: ld returned 1 exit status

As the manual stats:
gcj --main=LabelDialog LabelDialog.java -o LabelDiablog
GCJ need to know which class to use for the main "main" method as each 
class may have one.
> When I try to make an executable file and run it I
> receive the following error
>> Exception in thread "main" java.lang.Error: not
> implemented
> at javax.swing.UIDefaults.put(java.lang.Object,
> java.lang.Object) (/usr/lib/libgcj.so.4.0.0)
> at
> javax.swing.plaf.basic.BasicDefaults.BasicDefaults()
> (/usr/lib/libgcj.so.4.0.0)
> at
> javax.swing.plaf.metal.MetalLookAndFeel.getDefaults()
> (/usr/lib/libgcj.so.4.0.0)
> at javax.swing.UIManager.getDefaults()
> (/usr/lib/libgcj.so.4.0.0)
> at
> javax.swing.UIManager.getUI(javax.swing.JComponent)
> (/usr/lib/libgcj.so.4.0.0)
> at javax.swing.JPanel.updateUI()
> (/usr/lib/libgcj.so.4.0.0)
> at
> javax.swing.JPanel.JPanel(java.awt.LayoutManager,
> boolean) (/usr/lib/libgcj.so.4.0.0)
> at javax.swing.JPanel.JPanel()
> (/usr/lib/libgcj.so.4.0.0)
> at javax.swing.JRootPane.createGlassPane()
> (/usr/lib/libgcj.so.4.0.0)
> at javax.swing.JRootPane.getGlassPane()
> (/usr/lib/libgcj.so.4.0.0)
> at javax.swing.JRootPane.JRootPane()
> (/usr/lib/libgcj.so.4.0.0)
> at javax.swing.JFrame.createRootPane()
> (/usr/lib/libgcj.so.4.0.0)
> at javax.swing.JFrame.getRootPane()
> (/usr/lib/libgcj.so.4.0.0)
> at javax.swing.JFrame.frameInit()
> (/usr/lib/libgcj.so.4.0.0)
> at javax.swing.JFrame.JFrame()
> (/usr/lib/libgcj.so.4.0.0)
> at LabelDialog.main(java.lang.String[]) (Unknown
> Source)
>> Could you help me with this problem?

The stacktrace shows that this is not implemented in gcj 3.3. In gcj 
3.4.1 and 3.5.0 your example works (partly).
Michael