1. How to read a String line by line
(Java SE Tips/java.io)

...           if (str.length() > 0) System.out.println(str.charAt(0));          &nb...

2. Connecting GMail using POP3 connection with SSL
(Other API Tips/JavaMail)

...e(int messageNo) throws Exception {         System.out.println("Getting message number: " + messageNo); ...

3. How to crop a subimage from an image
(Java SE Tips/java.awt.image)

...     {             System.out.println("raster format error: " + rfe.getMessage()...

4. Introduction to Servlet Listener using Eclipse
(Java Tutorials/Tutorials)

...;public void contextInitialized(ServletContextEvent arg0) {     System.out.println("Servlet Context is initialized....");  &nbsp...

5. Introduction to Servlet Listener using NetBeans
(Java Tutorials/Tutorials)

...;public void contextInitialized(ServletContextEvent arg0) {     System.out.println("Servlet Context is initialized....");  &nbsp...

6. Limit a TextField to Uppercase
(Java SE Tips/java.awt)

... {                 System.exit(0);             } ...

7. Preventing multiple instances of an application
(Java SE Tips/java.lang)

...                 // System.out.println("*** Got a connection! ");    ...

8. Use arrays
(Other API Tips/JNI)

...sp;       static {         System.loadLibrary("javahowto");     } } ...

9. Set the computer clock
(Other API Tips/JNI)

Define the following prototype in the header file JNIEXPORT void JNICALL Java_JavaHowTo_setSystemTime (JNIEnv *, jobject, jshort, jshort); the JNI function JNIEXPORT void JNICALL J

10. Call events on a Frame from a Panel
(Java SE Tips/java.awt.event)

...;(ae.getSource()==p1.b1) {             System.out.println(ae.getActionCommand());         &...

11. Detect the mouse button used when clicking
(Java SE Tips/java.awt.event)

...p;  case InputEvent.BUTTON1_MASK: {         System.out.println("That's the LEFT button");    &n...

12. React to the ENTER key in a Textfield
(Java SE Tips/java.awt.event)

...kit.getDefaultToolkit().beep();             System.out.println("ENTER pressed");        ...

13. Convert RGB value to Hexadecimal - To be used in HTML for example
(Java SE Tips/java.awt)

...    if (args.length != 3) {       System.out.println("Color2Hex  r g b");     ...

14. Have a popup attached to a JTree
(Java SE Tips/javax.swing)

...sp;     win.setVisible(false);         System.exit(0);     } } class MyJTree extends JTre...

15. Read a data file into a JTable
(Java SE Tips/javax.swing)

...sp;     win.setVisible(false);         System.exit(0);     } } ...

16. Read a data file into a JTable and reload if data file have changed
(Java SE Tips/javax.swing)

...sp;     win.setVisible(false);         System.exit(0);     } } The DataFileW...

17. Validate a value on the lostFocus event
(Java SE Tips/javax.swing)

...when the lostFocus occurs on a Component, the gainedFocus is already sent for the next component in the SystemEventQueue. We must grab this event, and request the focus for the previous component ...

18. Keep the console open after execution
(Java SE Tips/java.io)

...put =        new BufferedReader(new InputStreamReader(System.in));     System.out.print("Press any key..."...

19. Make a JAR executable
(Java SE Tips/java.lang)

...{                  System.exit(0);             &nbs...

20. Pause the execution
(Java SE Tips/java.lang)

...p; public static void main(String args[]) {      System.out.println("Wait one second");      Wait....

21. Add/Substract Day/Month/Year to a Date
(Java SE Tips/java.util)

...Calendar.getInstance();  c1.set(1999, 0 , 20); // 1999 jan 20 System.out.println("Date is : " + sdf.format(c1.getTime())); ...

22. Compare two dates
(Java SE Tips/java.util)

...bsp; c2.set(1999, 0 , 30);           System.out.print(sdf.format(c1.getTime()));         &nb...

23. Post a message on a news server using NNTP protocol
(Java SE Tips/java.net)

...");     PrintStream p = c.startPost();     System.out.println("Starting post at " + args[0] + ...

24. Read messages from a news server
(Java SE Tips/java.net)

...;BufferedReader(new InputStreamReader(anArticle));         System.out.println("-----------------\nArticle " + i);   &n...

25. Get a list of headers from a newsgroup
(Java SE Tips/java.net)

...nbsp;     String theLine;         System.out.println("-----------------\nHeader " + i + "/&...

26. Get a list of all available newsgroup from a news server
(Java SE Tips/java.net)

...er = "news";     try {       System.out.println("opening server");       NntpC...

27. Compute days between 2 dates
(Java SE Tips/java.util)

...;   Integer.parseInt(args[5]), 0, 0, 0);      System.out.println        (daysBetween(c1.getTime(),c2.ge...

28. Get the Date from server
(Java SE Tips/java.net)

...(String args[]) {   if (args.length != 1) {    System.out.println("Usage: GetTime HOST");    return; &nb...

29. Latest Additions - 17.07.06 (389 new tips)
(Newsflashes/NewsFlashes)

...re screenshot How to use AWT CardLayout How to use Robot class in Java Java Graphics Coordinate System Converting RGB colors into values of hue saturation and intensity How to use Bord...

30. Get the last-modified date from a file
(Java SE Tips/java.io)

Simply use the lastModified() method from a file object. but the return value is system dependent and should only be used to compare with other values returned by last modified. It should not be int

31. Check if a file exists
(Java SE Tips/java.io)

...bsp;{     File f = new File(args[0]);     System.out.println       (f + (f.exists()? "...

32. Delete files with a certain extension
(Java SE Tips/java.io)

...p;public static void main (String args[]) {      System.out.println("hello");      delfile td =&nb...

33. Read a file into a variable in one shot
(Java SE Tips/java.io)

...#34;);        /* */        System.out.println(result);        }    ...

34. Read a text file from a jar
(Java SE Tips/java.io)

...readLine()) != null) {            System.out.println(thisLine);          } &nbs...

35. Redirect standard output to a file
(Java SE Tips/java.lang)

This tip shows how to redirect standard output (stdout) to a file. System.setOut(     new PrintStream(       ne

36. Check if a page exists
(Java SE Tips/java.net)

...heck { public static void main(String s[]) {     System.out.println(exists("http://www.java-tips.org/home/"));    &nbs...

37. Get the content of a directory with subdirectories
(Java SE Tips/java.io)

...nbsp;   if (arg.length > 0) {       System.out.println("recursive Dirs from " + arg[0]);  ...

38. Get the content of a directory with a Filter
(Java SE Tips/java.io)

...   if (args.length != 1) {        System.err.println ("usage: java Filter   ex. java&nbsp...

39. Access parameters passed in the URL
(Java SE Tips/java.applet)

...int i;   String completeURL = getDocumentBase().toString();   System.out.println("Complete URL: " + completeURL);   ...

40. Get the user name
(Java SE Tips/java.lang)

...or it or use a signed applet. String username; username = System.getProperty("user.name"); ...

41. Output french characters to the console
(Java SE Tips/java.io)

...edWriter            (new OutputStreamWriter(System.out, "Cp850"));       w.write(javaString);...

42. Wrap a Java beans in a COM object
(Other API Tips/JNI)

...u execute it from the sun.beans.ole package. The Java Plug-in 1.2 and the JDK1.2 must be installed on the system (for download, see Java Sun Web site). Let's try it with this simple class : ...

43. Wrap a Java class in a COM object
(Other API Tips/JNI)

... The class can compiled with any JDK but the actual execution will use the Microsoft JVM installed on the system. The javareg utility is part of the Microsoft Java SDK which can be freely download...

44. Create a Java source dynamically, compile and call
(Java SE Tips/java.lang)

...);     if (mtc.compileIt()) {        System.out.println("Running " + mtc.todayClass + ":\n\n&#...

45. Access the enclosing class from an inner class
(Java SE Tips/java.lang)

... }   public void enclosingClassMethod(){       System.out.println("Hello world!");       } &nb...

46. Calling a method dynamically using reflection
(Java SE Tips/java.lang.reflect)

...bsp;  // call the method          System.out.println(thisMethod.invoke(iClass, paramsObj).toString());    ...

47. Replace or remove character in a String
(Java SE Tips/java.lang)

...sp;"; String   tmpString = myString.replace( '\'', '*' ); System.out.println( "Original = " + myString ); System...

48. Use a Hashtable
(Java SE Tips/java.util)

...  String[] resultArray = (String[])(arrays.get("Array2"));   System.out.println     (resultArray[0] + ", "&nbs...

49. Have an applet launch another applet
(Java SE Tips/java.applet)

...sp;}     catch (Exception e) {       System.out.println( e );       }   &nbsp...

50. How to use an INI file
(Java SE Tips/java.util)

...p;  p.load(new FileInputStream("user.ini"));       System.out.println("user = " + p.getProperty("DBuser")); ...