Explore topic-wise InterviewSolutions in .

Correct choice is (c) JAVA.home

To explain I WOULD SAY: java.home is the INSTALLATION directory of Java Runtime Environment.

Correct choice is (a) True

To explain I would say: Java SYSTEM PROPERTIES can be SET at RUNTIME using System.setProperty(name, value) or using System.getProperties().load() METHODS.

Right ANSWER is (B) Java system properties are accessible by PROCESSES they are ADDED to

For explanation: Java system properties are only USED and accessible by the processes they are added.

Right choice is (c) PROCESSBUILDER

The best I can explain: Java APPLICATION uses ProcessBuilder object to create a new process. By default, same set of ENVIRONMENT VARIABLES passed which are set in application’s virtual machine process.

Right option is (a) SLEEP()

The best EXPLANATION: NONE.

Right ANSWER is (a) Runnable INTERFACE

Explanation: Runnable interface defines all the METHODS for handling THREAD OPERATIONS in Java.

Correct choice is (c) THREAD

Best EXPLANATION: Thread CLASS is used to make threads in java, Thread encapsulates a thread of EXECUTION. To create a new thread the program will either extend Thread or IMPLEMENT the Runnable interface.

Right option is (B) TotalMemory()

To ELABORATE: TotalMemory() returns the TOTAL number of BYTES AVAILABLE to the program.

The correct ANSWER is (C) SecurityException

The best I can EXPLAIN: EVERY method of Runtime class THROWS SecurityException.

The CORRECT ANSWER is (C) Runtime

Easiest EXPLANATION: NONE.

The CORRECT choice is (c) JAVA 2.0

Easiest explanation: toRadian() and TODEGREE() methods were ADDED by Java 2.0 before that there was no method which could directly convert degree into radians and vice VERSA.

The correct CHOICE is (d) IEEEremainder()

EXPLANATION: IEEEremainder() returns the REMAINDER of DIVIDEND / DIVISOR.

Correct OPTION is (B) RANDOM()

BEST explanation: NONE.

The correct choice is (b) StrictMath

Easy EXPLANATION: SystemMath class defines a complete set of MATHEMATICAL methods that are parallel those in Math class. The DIFFERENCE is that the StrictMath version is guaranteed to GENERATE precisely identical results across all Java implementations.

Correct OPTION is (d) All of the mentioned

Explanation: Boolean wrapper defines 3 constants – TRUE, FALSE & TYPE.

The CORRECT CHOICE is (C) isJavaIdentifierPart()

For EXPLANATION: NONE.

Right choice is (d) Number

Explanation: Number is an abstract CLASS containing SUBCLASSES DOUBLE, FLOAT, Byte, Short, CHARACTER, Integer and Long.

Correct ANSWER is (c) charValue()

Easy explanation: To obtain the CHAR VALUE CONTAINED in a Character OBJECT, we use charValue() method.

The correct choice is (d) All of the mentioned

The best EXPLANATION: Character wrapper DEFINES 5 constants – MAX_RADIX, MIN_RADIX, MAX_VALUE, MIN_VALUE & TYPE.

Right option is (c) DECODE()

Explanation: decode() methods returns a Byte OBJECT that CONTAINS the value SPECIFIED by string.

The correct answer is (a) double ceil(double X)

Explanation: ceil(double X) RETURNS the SMALLEST WHOLE number greater than or EQUAL to variable X.

The correct CHOICE is (b) double FLOOR(double X)

Best explanation: double floor(double X) returns a largest whole NUMBER less than or equal to VARIABLE X.

Right CHOICE is (b) NullPointerException

For explanation: If we USE null REFERENCE ANYWHERE in the code where the value stored in that reference is used then NullPointerException occurs.

The CORRECT CHOICE is (a) Math

The BEST EXPLANATION: NONE.

Right choice is (d) NegativeArraySizeExeption

Easiest EXPLANATION: Array size must always be positive if we declare an array with NEGATIVE size then BUILT in exception “NegativeArraySizeException” is thrown by the java’s RUN TIME system.

Correct CHOICE is (b) JAVA Heap

Easy EXPLANATION: When a string is created; if the string already exists in the pool, the reference of the EXISTING string will be RETURNED, else a new object is created and its reference is returned.

Right answer is (d) Permanent space

To elaborate: The permanent generation holds objects which JVM finds CONVENIENT to have the garbage COLLECTOR. Objects DESCRIBING classes and methods, as WELL as the classes and methods themselves,are a part of Permanent generation.

The correct answer is (C) Metaspace

Easiest explanation: Metaspace is the REPLACEMENT of PermGen in Java 8. It is very similar to PermGen EXCEPT that it resizes itself dynamically. THUS, it is unbounded.

Right OPTION is (d) Temporary

To explain: Young generation is further CLASSIFIED into Eden space and Survivor space. Old generation is ALSO the tenured space. The PERMANENT generation is the non HEAP space.

The CORRECT answer is (B) Extension

To explain: Extension loads jar files from lib/ext directory of the JRE. This gives the BASIC functionality AVAILABLE.

Correct ANSWER is (a) BOOTSTRAP

For explanation I WOULD SAY: Bootstrap is a CLASS loader. It loads the classes into memory.

Right option is (a) True

The EXPLANATION: Code Segment loads COMPILED JAVA bytecode. Bytecode is platform independent.

Right option is (b) Interpreter

Best explanation: JVM is Interpreter. It READS .CLASS FILES which is the byte code GENERATED by COMPILER line by line and converts it into native OS code.

Correct answer is (d) Register Segment

Explanation: There are only 3 types of MEMORY segment. STACK Segment, Heap Segment and CODE Segment.

Correct choice is (c) CharArrayReader

Best EXPLANATION: CharArrayReader is an implementation of an INPUT stream that USES character array as a source. Here array is the input source.

The correct answer is (C) CHARACTER Stream

Easiest explanation: InputStream & OutputStream classes under byte stream they are not streams. Character Stream CONTAINS all the classes which can WORK with Unicode.