Java Multiple Choice Questions & Answers on Java.lang package System Class Advance for Freshers

1. Which of these exceptions is thrown by methods of System class?

a) IOException
b) SystemException
c) SecurityException
d) InputOutputException

Answer: c

Explanation: System class methods throw SecurityException.

2. Which of these methods initiates garbage collection?

a) gc()
b) garbage()
c) garbagecollection()
d) Systemgarbagecollection()

Answer: a

3. Which of these methods loads the specified dynamic library?

a) load()
b) library()
c) loadlib()
d) loadlibrary()

Answer: a

Explanation: load() methods loads the dynamic library whose name is specified.

4. Which of these method can set the out stream to OutputStream?

a) setStream()
b) setosteam()
c) setOut()
d) streamtoOstream()

Answer: c

5. Which of these values are returns under the case of normal termination of a program?

a) 0
b) 1
c) 2
d) 3

Answer: a

6. What is the output of this program?

1.     import java.lang.System;

2.     class Output {

3.          public static void main(String args[]) {

4.              long start, end;   

5.              start = System.currentTimeMillis();

6.              for (int i = 0; i < 10000000; i++);

7.              end = System.currentTimeMillis();

8.              System.out.print(end - start);

9.         }

10.     }

a) 0
b) 1
c) 1000
d) System Dependent

Answer: d

Explanation: end time is the time taken by loop to execute it can be any non zero value depending on the System.

7. What is the output of this program?

1.     import java.lang.System;

2.     class Output {

3.         public static void main(String args[]) {

4.             byte a[] = { 65, 66, 67, 68, 69, 70 };

5.             byte b[] = { 71, 72, 73, 74, 75, 76 };  

6.             System.arraycopy(a, 0, b, 0, a.length);

7.             System.out.print(new String(a) + " " + new String(b));

8.         }

9.     }

a) ABCDEF ABCDEF
b) ABCDEF GHIJKL
c) GHIJKL ABCDEF
d) GHIJKL GHIJKL

Answer: a

Explanation: System.arraycopy() is a method of class System which is used to copy a string into another string.

8. What is the output of this program?

1.     import java.lang.System;

2.     class Output {

3.         public static void main(String args[]) {

4.             byte a[] = { 65, 66, 67, 68, 69, 70 };

5.             byte b[] = { 71, 72, 73, 74, 75, 76 };  

6.             System.arraycopy(a, 0, b, 3, a.length - 3);

7.             System.out.print(new String(a) + " " + new String(b));

8.         }

9.     }

a) ABCDEF ABCDEF
b) ABCDEF GHIJKL
c) ABCDEF GHIABC
d) GHIJKL GHIJKL

Answer: c

Explanation: System.arraycopy() is a method of class System which is used to copy a string into another string.

9. What is the output of this program?

1.     import java.lang.System;

2.     class Output {

3.         public static void main(String args[]) {

4.             byte a[] = { 65, 66, 67, 68, 69, 70 };

5.             byte b[] = { 71, 72, 73, 74, 75, 76 };  

6.             System.arraycopy(a, 2, b, 3, a.length - 4);

7.             System.out.print(new String(a) + " " + new String(b));

8.         }

9.     }

a) ABCDEF ABCDEF
b) ABCDEF GHIJKL
c) ABCDEF GHIABC
d) ABCDEF GHICDL

Answer: d

Explanation: System.arraycopy() is a method of class System which is used to copy a string into another string.

10. What value will this program return to Java run-time system?

1.     import java.lang.System;

2.     class Output {

3.         public static void main(String args[]) {

4.             System.exit(5);

5.         }

6.     }

a) 0
b) 1
c) 4
d) 5

Answer: d