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Java Tutorial » Reflection » Class  
7.1.11.Demonstration of how to obtain instances of java.lang.ClassPrevious/Next
/*
 *     file: ObtainingClassInstances.java
 *  package: oreilly.hcj.reflection
 *
 * This software is granted under the terms of the Common Public License,
 * CPL, which may be found at the following URL:
 * http://www-124.ibm.com/developerworks/oss/CPLv1.0.htm
 *
 * Copyright(c) 2003-2005 by the authors indicated in the @author tags.
 * All Rights are Reserved by the various authors.
 *
########## DO NOT EDIT ABOVE THIS LINE ########## */


/**  
 * Demonstration of how to obtain instances of <tt>java.lang.Class</tt>.
 *
 @author <a href=mailto:kraythe@arcor.de>Robert Simmons jr. (kraythe)</a>
 @version $Revision: 1.3 $
 */
public class ObtainingClassInstances {
  /** An Integer object */
  protected static Integer someInteger = new Integer(10);

  /** A generic object. */
  protected static Object someObject = null;

  /** A String. */
  protected static String someString = new String("Hardcore Java");

  /** An int. */
  protected static int someInt = 15;

  /** An array of ints. */
  protected static int[] intArray = new int[] { 457};

  /** 
   * Main method.
   *
   @param args Command line arguments.
   */
  public static void main(final String[] args) {
    // -- Print out the Class instances. 
    System.out.println(someInteger.getClass());
    System.out.println(someString.getClass());
    System.out.println(intArray.getClass());
    System.out.println(Object.class);
    System.out.println(Integer.class);
    System.out.println(int.class);
    System.out.println(String.class);
    System.out.println(Comparable.class);
    System.out.println(Object[].class);

    // -- Things that WON'T work
    // System.out.println(someObject.getClass());  // <= Exception 
    // System.out.println(someInt.getClass()); // <= Compiler errror
  }

  /** 
   * Demonstration of a method that doesnt check for null.
   *
   @param obj The object passed.
   */
  public void writeClass(final Object obj) {
    System.out.println(obj.getClass());
  }
}

/* ########## End of File ########## */
7.1.Class
7.1.1. Get class name for various object
7.1.2. Create new instance
7.1.3. Get Canonical Name for a class
7.1.4. Demonstrates the use of getDeclaringClass()
7.1.5. Demonstrates the use of instance comparisons
7.1.6. Demonstrates usage of various class information methods
7.1.7. Demonstrates how to get declaration information on a Class
7.1.8. Demonstrates Dynamic class type checking
7.1.9. Demonstrates how to set public field objects
7.1.10. Demonstrates fetching nested class info from a Class object
7.1.11. Demonstration of how to obtain instances of java.lang.Class
7.1.12. Demonstrates getting immediate superclass info
7.1.13. Get declared method by name and parameter type
7.1.14. get class from an object
7.1.15. Returns the name of a class without the package name
7.1.16. Class comparator: compare and sort classes and their superclasses.
7.1.17. Is Type Compatible
7.1.18. Is the Same Signature
7.1.19. Determine whether the supplied string represents a well-formed fully-qualified Java classname.