Hello world

Without a GUI:

import os
import javabridge

javabridge.start_vm(run_headless=True)
try:
    print javabridge.run_script('java.lang.String.format("Hello, %s!", greetee);',
                                dict(greetee='world'))
finally:
    javabridge.kill_vm()

You can also use a with block:

import os
import javabridge

with javabridge.vm(run_headless=True)
    print javabridge.run_script('java.lang.String.format("Hello, %s!", greetee);',
                                dict(greetee='world'))

With only a Java AWT GUI:

import os
import wx
import javabridge

javabridge.start_vm()

class EmptyApp(wx.App):
    def OnInit(self):
        javabridge.activate_awt()
        return True

try:

    app = EmptyApp(False)

    # Must exist (perhaps the app needs to have a top-level window?), but
    # does not have to be shown.
    frame = wx.Frame(None)

    javabridge.execute_runnable_in_main_thread(javabridge.run_script("""
                new java.lang.Runnable() {
                    run: function() {
                        with(JavaImporter(java.awt.Frame)) Frame().setVisible(true);
                    }
                };"""))

    app.MainLoop()

finally:

    javabridge.kill_vm()

Mixing wxPython and Java AWT GUIs:

import os
import wx
import javabridge

class EmptyApp(wx.PySimpleApp):
    def OnInit(self):
        javabridge.activate_awt()

        return True

javabridge.start_vm()

try:
    app = EmptyApp(False)

    frame = wx.Frame(None)
    frame.Sizer = wx.BoxSizer(wx.HORIZONTAL)
    launch_button = wx.Button(frame, label="Launch AWT frame")
    frame.Sizer.Add(launch_button, 1, wx.ALIGN_CENTER_HORIZONTAL)

    def fn_launch_frame(event):
        javabridge.execute_runnable_in_main_thread(javabridge.run_script("""
        new java.lang.Runnable() {
            run: function() {
                with(JavaImporter(java.awt.Frame)) Frame().setVisible(true);
            }
        };"""))
    launch_button.Bind(wx.EVT_BUTTON, fn_launch_frame)

    frame.Layout()
    frame.Show()
    app.MainLoop()

finally:

    javabridge.kill_vm()