Java: Out with the Old, In with the New

public static final int CLUBS = 0;
public static final int DIAMONDS = 1;
public static final int HEARTS = 2;
public static final int SPADES = 3;

public enum Suit {
  CLUBS,
  DIAMONDS,
  HEARTS,
  SPADES
}

List l = someList;
Iterator i = l.getIterator();
while (i.hasNext()) {
    MyObject o = (MyObject)i.next();
}

List<MyObject> l = someList;
for (MyObject o : l) {
    //do something
}

try {
    BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
    String str = reader.readLine();
    reader.close();
}
catch (IOException e) {
    System.err.println("error when closing input stream.");
}

Scanner reader = new Scanner(System.in);
String str = reader.nextLine();
reader.close();

Console reader = System.console();
String str = reader.readLine();

public int add(int... numbers){
    int sum = 0 ;
    for (int i : numbers){
        sum+=i;
    }
    return sum ;
}

public int add(int n1, int n2, int n3, int n4) ;

public int add(List<Integer> numbers) ;

Integer myInteger = 6;
int myInt = myInteger.intValue();

Integer myInteger = 6;
int myInt = myInteger;

String str = "test " + intValue + " test " + doubleValue;

String str = String.format("test %d test %lg", intValue, doubleValue);

myframe.getContentPane().add(mycomponent);

myframe.add(mycomponent);

import static Math.* ;

Vector stringVector = new Vector();
stringVector.add("hi");
stringVector.add(528); // oops!
stringVector.add(new Whatzit());  // Oh my, could spell trouble later on!

ArrayList<String> stringList = new ArrayList<String>();
stringList.add("hello again");
stringList.add(new Whatzit()); // Won't compile!

List list = getTheList();
Iterator iter = list.iterator()
while (iter.hasNext()) {
  String s = (String) iter.next();
    // .. do something
}

List list = getTheList();
for (Iterator iter = list.iterator(); iter.hasNext();) {
  String s = (String) iter.next();
  // .. do something
}

List<String> list = getTheList();
for (String s : list) {
  // .. do something
}

String s = n + "";

String s = String.valueOf(n);

// AGGHHH!!!
int[] array = new int[] {0, 1, 2, 3, 4};
for (int i = 0; i < array.length; i++)
{
    // Do something...
}

// Nice and clean.
int[] array = new int[] {0, 1, 2, 3, 4};
for (int n : array)
{
    // Do something...
}

int[] src = new int[] {1, 2, 3, 4, 5};
int[] dest = new int[src.length];
System.arraycopy(src, 0, dest, 0, src.length);

int[] src = new int[] {1, 2, 3, 4, 5};
int[] dest = Arrays.copyOf(src, src.length);

List<String> items = new ArrayList<String>();
items.add("one");
items.add("two");
items.add("three");
handleItems(items);

handleItems(Arrays.asList("one", "two", "three"));

class Test extends TestCase {
    public void testYadaYada() { ... }
}

class Test {
   @Test public void yadaYada() { ... }
}

String s1 = "...", s2 = "...";

if (s1.intern() == s2.intern()) {
    ....
}

String s1 = "...", s2 = "...";

if (s1.equals(s2)) {
    ....
}

public class Enum
  {
      public static final Enum FOO = new Enum();
      public static final Enum BAR = new Enum();
  }

public enum Singleton {
    INSTANCE;

    public void someMethod() {
        ...
    }
}

public class Singleton {
    public static final Singleton INSTANCE = new Singleton();

    private Singleton() {
        ...
    }

    public void someMethod() {
        ...
    }
}