Questions and Answers

91. What is the Map interface? The Map interface replaces the JDK 1.1 Dictionary class and is used associate keys with values.

85. How is rounding performed under integer division? The fractional part of the result is truncated. This is known as rounding toward zero.

79. When can an object reference be cast to an interface reference? An object reference be cast to an interface reference when the object implements the referenced interface.

61. What method is invoked to cause an object to begin executing as a separate thread? The start() method of the Thread class is invoked to cause an object to …

55. How many times may an object’s finalize() method be invoked by the garbage collector? An object’s finalize() method may only be invoked once by the garbage collector.

37. What are order of precedence and associativity, and how are they used? Order of precedence determines the order in which operators are evaluated in expressions. Associatity determines whether an …

25. What are wrapped classes? Wrapped classes are classes that allow primitive types to be accessed as objects. 26. Does garbage collection guarantee that a program will not run out …

7. What’s new with the stop(), suspend() and resume() methods in JDK 1.2? The stop(), suspend() and resume() methods have been deprecated in JDK 1.2. 8. Is null a keyword? …

1. What is a transient variable? A transient variable is a variable that may not be serialized. 2. Which containers use a border Layout as their default layout? The Window, …

97. Difference between Swing and Awt? AWT are heavy-weight componenets. Swings are light-weight components. Hence swing works faster than AWT.