31. Which class is the superclass for every class.
Object
32. What invokes a thread’s run() method?
After a thread is started, via its start() method or that of the Thread class, the JVM invokes the thread’s run() method when the thread is initially executed.
33. What is the difference between the Boolean & operator and the && operator?
If an expression involving the Boolean & operator is evaluated, both operands are evaluated. Then the & operator is applied to the operand. When an expression involving the && operator is evaluated, the first operand is evaluated. If the first operand returns a value of true then the second operand is evaluated. The && operator is then applied to the first and second operands. If the first operand evaluates to false, the evaluation of the second operand is skipped.
Operator & has no chance to skip both sides evaluation and && operator does. If asked why, give details as above.
34. What is the GregorianCalendar class?
The GregorianCalendar provides support for traditional Western calendars.
35. What is the SimpleTimeZone class?
The SimpleTimeZone class provides support for a Gregorian calendar.
36. Which Container method is used to cause a container to be laid out and redisplayed?
validate()
37. What is the Properties class?
The properties class is a subclass of Hashtable that can be read from or written to a stream. It also provides the capability to specify a set of default values to be used.
38. What is the purpose of the Runtime class?
The purpose of the Runtime class is to provide access to the Java runtime system.
39. What is the purpose of the System class?
The purpose of the System class is to provide access to system resources.
40. What is the purpose of the finally clause of a try-catch-finally statement?
The finally clause is used to provide the capability to execute code no matter whether or not an exception is thrown or caught.
Object
32. What invokes a thread’s run() method?
After a thread is started, via its start() method or that of the Thread class, the JVM invokes the thread’s run() method when the thread is initially executed.
33. What is the difference between the Boolean & operator and the && operator?
If an expression involving the Boolean & operator is evaluated, both operands are evaluated. Then the & operator is applied to the operand. When an expression involving the && operator is evaluated, the first operand is evaluated. If the first operand returns a value of true then the second operand is evaluated. The && operator is then applied to the first and second operands. If the first operand evaluates to false, the evaluation of the second operand is skipped.
Operator & has no chance to skip both sides evaluation and && operator does. If asked why, give details as above.
34. What is the GregorianCalendar class?
The GregorianCalendar provides support for traditional Western calendars.
35. What is the SimpleTimeZone class?
The SimpleTimeZone class provides support for a Gregorian calendar.
36. Which Container method is used to cause a container to be laid out and redisplayed?
validate()
37. What is the Properties class?
The properties class is a subclass of Hashtable that can be read from or written to a stream. It also provides the capability to specify a set of default values to be used.
38. What is the purpose of the Runtime class?
The purpose of the Runtime class is to provide access to the Java runtime system.
39. What is the purpose of the System class?
The purpose of the System class is to provide access to system resources.
40. What is the purpose of the finally clause of a try-catch-finally statement?
The finally clause is used to provide the capability to execute code no matter whether or not an exception is thrown or caught.
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