notes3

notes3 - • Java primitives (data types like int) are...

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Java primitives (data types like int ) are passed "by value". Objects are passed "by reference". e.g. class Foo { } Foo myfoo = new Foo(); //myfoo is a ref. to an object Foo newfoo = myfoo; //another ref to the object pointed //to by ref myfoo A reference is like a pointer to that object and this reference can be passed to a method. Then the receiving ref var will get a copy of the ref passed. Now two refs will point to this same object and can be used to alter the original object. e.g. mymethod(myfoo); Strings (and arrays) are objects in Java. Thus they are ref types. e.g. String s = "This is indeed "; The ' + ' symbol is the overloaded operator in Java and is used to concatenate strings. e.g. String s = s + "funny"; String objects have a length method. E.g. int len = s.length(); The type of an expression is known at compile-time in Java. Control statements include: if ( . . ) { } else { . .} while (…) { …. . } switch (….) { case intexpr: statement1; break; default: statement2; }
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Java does not allow pointer manipulation. So no *, and & operators. The expression null can be assigned to any reference type. It
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This note was uploaded on 07/29/2011 for the course CNT 6707 taught by Professor Ahuja during the Spring '11 term at UNF.

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notes3 - • Java primitives (data types like int) are...

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