Autoboxing - Revision history

Suhridk: /* Overloading */

2011-09-13T16:35:29Z

Overloading

2011-09-08T12:49:18Z

Overriding

2011-09-08T12:46:53Z

Overriding

2011-09-08T12:45:17Z

Overriding

2011-09-08T12:44:27Z

Overloading

2011-09-08T10:35:23Z

Assignments

2011-09-08T10:25:06Z

Assignments

2011-09-08T09:28:55Z

Assignments

2011-09-08T09:28:39Z

Assignments

2011-09-07T11:03:51Z

Assignments

@@ Line 277: / Line 277: @@
 * '''These wont work:'''
 <syntaxhighlight lang="java5">
@@ Line 340: / Line 363: @@
 </syntaxhighlight>
 == Overriding ==

@@ Line 370: / Line 370: @@
 </syntaxhighlight>
-* However, things are OK when it comes to method parameters.
+* However, things are OK when it comes to method parameters when extending classes.
 <syntaxhighlight lang="java5">
@@ Line 392: / Line 392: @@
 	public void bar(int i) { //OK
+	}

@@ Line 344: / Line 344: @@
 == Overriding ==
-* Autoboxing/Unboxing doesnt work when it comes to overrides. This is true while extending classes also.
+* Autoboxing/Unboxing doesnt work when it comes to overriding methods return types. This is true while extending classes also.
 <syntaxhighlight lang="java5">
@@ Line 367: / Line 367: @@
+}
 </syntaxhighlight>
 [[Category:OCPJP]]

@@ Line 344: / Line 344: @@
 == Overriding ==
-* Autoboxing/Unboxing doesnt work when it comes to overrides
+* Autoboxing/Unboxing doesnt work when it comes to overrides. This is true while extending classes also.
 <syntaxhighlight lang="java5">

← Older revision		Revision as of 12:44, 8 September 2011
Line 341:		Line 341:
	</syntaxhighlight>		</syntaxhighlight>

		+
		+	== Overriding ==
		+
		+	* Autoboxing/Unboxing doesnt work when it comes to overrides
		+
		+	<syntaxhighlight lang="java5">
		+
		+
		+	interface A {
		+
		+	public int foo();
		+
		+	public Integer bar();
		+	}
		+
		+	class B implements A {
		+
		+	public Integer foo() { //WONT COMPILE - has to return int
		+	return new Integer(42);
		+	}
		+
		+	public int bar() { //WONT COMPILE - has to return Integer
		+	return 42;
		+	}
		+	}
		+
		+
		+	</syntaxhighlight>

	[[Category:OCPJP]]		[[Category:OCPJP]]

← Older revision		Revision as of 10:35, 8 September 2011
Line 119:		Line 119:

	s1 = (short) (s1 * 10); //This is OK		s1 = (short) (s1 * 10); //This is OK
		+
		+	</syntaxhighlight>
		+
		+	* Assigning Wrappers to primitives
		+
		+	* For the same type unboxing will happen.
		+	* For narrower types casting needs to be added.
		+
		+	<syntaxhighlight lang="java5">
		+
		+	Integer iref = 10;
		+
		+	short s = (short) iref.intValue();
		+
		+	Byte bo = 20;
		+
		+	long lp = bo; //OK - bo is unboxed to a byte which can be widened to a long

	</syntaxhighlight>		</syntaxhighlight>

← Older revision		Revision as of 10:25, 8 September 2011
Line 106:		Line 106:
	Byte c3 = (byte) b1 + b2; //OK - note cast is for byte and not Byte.		Byte c3 = (byte) b1 + b2; //OK - note cast is for byte and not Byte.

		+
		+	</syntaxhighlight>
		+
		+	* Compound assignment operators are not allowed on Wrappers smaller than Integer
		+	* Because the result of the operation in an integer which cannot be cast to the Wrapper Type.
		+
		+	<syntaxhighlight lang="java5">
		+
		+	Short s1 = 10;
		+
		+	s1 *= 10; //Wont work
		+
		+	s1 = (short) (s1 * 10); //This is OK

	</syntaxhighlight>		</syntaxhighlight>

@@ Line 88: / Line 88: @@
 Double d = 4.5; //OK - 4.5 is double by default.
-short s = 11;
+short s2 = 11;
-Integer iref = s; //NOT OK. a Short is NOT-A Integer
+Integer iref = s2; //NOT OK. a Short is NOT-A Integer
 </syntaxhighlight>

← Older revision		Revision as of 11:03, 7 September 2011
Line 100:		Line 100:

	Byte c3 = (byte) b1 + b2; //OK - note cast is for byte and not Byte.		Byte c3 = (byte) b1 + b2; //OK - note cast is for byte and not Byte.
		+

	</syntaxhighlight>		</syntaxhighlight>