Mock java Questions set - 4

Sun Certified Java Programmer(SCJP 1.4)
MockQuestions - 20
Mock Exam - 4
Q1
public class Test1{
static void method(Object obj){
System.out.println("Object");
}
static void method(String str){
System.out.println("String");
}
public static void main(String args[]){
method(null);
}
}
What will be the output?
A1 String
A2 Object
A3 null
A4 Compiler Error
Q2
public class Test2{
static void method(StringBuffer obj){
System.out.println("StringBuffer");
}
static void method(String str){
System.out.println("String");
}
public static void main(String args[]){
method(null);
}
}
What will be the output?
A1 String
A2 Object
A3 null
A4 Compiler Error
class Test{}
public class Test3{
static void method(Object obj){
Q3
System.out.println("StringBuffer");
}
static void method(String str){
System.out.println("String");
}
static void method(Test t){
System.out.println("Test");
}
public static void main(String args[]){
method(null);
}
}
What will be the output?
A1 String
A2 Object
A3 Test
A4 Compiler Error
Q4
public class Test4{
public static void main(String args[]){
I i1 = new A();
I i2 = new B();
A a = new A();
System.out.println(i1 instanceof I);
System.out.println(i2 instanceof B);
System.out.println(a instanceof I);
}
}
interface I{}
class A implements I{}
class B implements I{}
What will be the output?
A1 true true true
A2 true false true
A3 true false false
A4 Compiler Error
Q5
public class Test5{
public static void main(String args[]){
System.out.println(I.k);
}
}
interface I{
int k;
}
What will be the output?
A1 true true true
A2 true false true
A3 true false false
A4 Compiler Error
Q6
public class Test6 implements I{
int k = 1;
public static void main(String args[]){
System.out.println(k);
}
}
interface I{
int k = 0;
}
What will be the output?
A1 0
A2 1
A3 null
A4 Compiler Error
Q7
public class Test7 implements I{
int k = 1;
static{
k = k * 2;
}
{
k = k * 2;
}
public static void main(String args[]){
Test7 t1 = new Test7();
Test7 t2 = new Test7();
System.out.println(t1.k);
System.out.println(t2.k);
System.out.println(k);
}
}
What will be the output?
A1 0
A2 1
A3 null
A4 Compiler Error
Q8
public class Test8{
static int k = 1;
static{
k = k * 2;
}
{
k = k * 2;
}
public static void main(String args[]){
System.out.println(k);
}
}
What will be the output?
A1 1
A2 2
A3 4
A4 Compiler Error
Q9
public class Test9{
static int k = 1;
{
k = k * 2;
}
public static void main(String args[]){
System.out.println(k);
}
}
What will be the output?
A1 1
A2 2
A3 4
A4 Compiler Error
Q10
public class Test10{
final static int k;
static{
k = 0;
}
public static void main(String args[]){
System.out.println(k);
}
}
What will be the output?
A1 0
A2 1
A3 null
A4 Compiler Error
Answers
1 String
2 Compiler Error
3 Compiler Error
4 true true true
5 true true true
6 Compiler Error
7 Compiler Error
8 2
9 1
10 0
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