1.class C{
static int f1(int i) {
System.out.print(i + ",");
return 0;
}
public static void main (String[] args) {
int i = 0;
i = i++ + f1(i);
System.out.print(i);
}}
What is the result of attempting to compile and run the program?
1.Prints: 0,0
2.Prints: 1,0
3.Prints: 0,1
4.Compile-time error
5.None of the above
Answer: 2
2)
class C{
static String m(int i) {return "int";}
static String m(float i) {return "float";}
public static void main (String[] args) {
long a1 = 1; double b1 = 2;
System.out.print(m(a1)+","+ m(b1));
}}
What is the result of attempting to compile and run the program?
1.Prints: float,double
2.Prints: float,float
3.Prints: double,float
4.Compile-time error
5.None of the above
Answer: 4
3)
class C
{
public static void main(String a[])
{
C c1=new C();
C c2=m1(c1);
C c3=new C();
c2=c3; //6
anothermethod();
}
static C m1(C ob1){
ob1 =new C();
return ob1;
}
}
After line 6, how many objects are eligible for garbage collection?
1. 1
2. 2
3. 3
4. 4
5. None of the above
Answer: 2
4)
1. StringBuffer s1 = new StringBuffer("abc");
2. StringBuffer s2 = s1;
3. StringBuffer s3 = new StringBuffer("abc");
How many objects are created ?
1. 0
2. 1
3. 2
4. 3
Answer : 4
5)
class c2
{
{
System.out.println("initializer");
}
public static void main(String a[])
{
System.out.println("main");
c2 ob1=new c2();
}
}
What is the result of attempting to compile and run the program?
1.prints main and initializer
2.prints initializer and main
3.compile time error
4.None of the above
Answer: 1
6)
class c1
{
public static void main(String a[])
{
c1 ob1=new c1();
Object ob2=ob1;
System.out.println(ob2 instanceof Object);
System.out.println(ob2 instanceof c1);
}
}
What is the result of attempting to compile and run the program?
1.Prints true,false
2.Print false,true
3.Prints true,true
4.compile time error
5.None of the above
Answer: 3
7)
class A extends Thread {
private int i;
public void run() {i = 1;}
public static void main(String[] args) {
A a = new A();
a.run();
System.out.print(a.i);
}}
What is the result of attempting to compile and run the program?
1.Prints nothing
2.Prints: 1
3.Prints: 01
4.compile-time error
5.None of the above
Answer: 2
Explanation:
a.run() method was called instead of a.start(); so the full program runs as a single thread so a.run() is guaranteed to complete
8)
class bike
{
}
class arr extends bike{
public static void main(String[] args) {
arr[] a1=new arr[2];
bike[] a2;
a2=a1; //3
arr[] a3;
a3=a1; //5
}}
What is the result of attempting to compile and run the program?
1.compile time error at line 3
2.compile time error at line 5
3.Runtime exception
4.The code runs fine
5.None of the above
Answer: 4
Explanation:
bike is the superclass of arr.so they are compatible(superobject=subobject)
but subobject=superobject not allowed
9)
class C{
public static void main (String[] args) {
String s1="hjhh"; // 1
String s2="\u0002"; //2
String s3="'\\'"; //3
}}
What is the result of attempting to compile and run the program?
1.compile time error at line 1
2.compile time error at line 2
3.compile time error at line 3
4.Runtime exception
5.the code runs without any error
Answer: 5
Explanation:
A String literal is a sequence of characters enclosed in double quotes
10)
Which data type is wider for the purpose of casting: float or long?
1.float
2.long
Answer: 1
Explanation:
float is wider than long, because the entire range of long fits within the range of float.