This is a set of questions for those who are preparing for the java 2 programmer exam (SCJP)
The answers are at the bottom of this page.

Q1-The following program is in file Test.java, what would be the output
        of compiling and running this program ?

        class MyFirstClass{
                MyFirstClass(){
                        System.out.println("MyFirstClass created");
                }
        }

        public class Test{
                public static void main(String str[]){
                MyFirstClass mf = new MyFirstClass();
                MyThirdClass mf = new MyThirdClass();
                }
        }

        public class MyThirdClass{
                MyThirdClass(){
                        System.out.println("MyThirdClass created");
                }
        }

a) compiles, runs and does not print anything
b) does not compile
c) compiles, runs and prints "MyFirstClass created"
d) compiles, runs and prints "MyFirstClass created" and "MyThirdClass created"

        public class Test implements Runnable{
                public static void main(String str[]){
                Thread t = new Thread(new Test());
                }

                public void run(){
                        for(int i=0; i<10; i++){
                        System.out.println("t ");
                        }
                }
        }
 

a) does not compile
b) compiles, runs and prints " t t t t t t t t t t "
c) compiles and does not run
d) compiles, runs and does not print anything

        public class Test {
                public static void main(String str[]){
                System.out.print(5+5+"s"+6+6);
                }
        }

a) compiles, runs and prints " 10s66 "
b) compiles, runs and prints " 10s12 "
c) compiles, runs and prints " 55s66 "
d) compiles, runs and does not print anything

        public class Test {
                static private String st;
                public static void main(String str[]){
                        System.out.print(st+"yes");
                }
        }

a) compiles, runs and prints " yes "
b) does not compiles
c) compiles, runs and prints " nullyes "
d) compiles, runs and prints " null+yes "

        public class Test {
                public Test(float f){
                        printMessage(f);
                }

                public void printMessage(float f){
                        System.out.println("object "+"number "+f+" created");
                }

                public static void main(String str[]){
                        Test t1;
                        Test t2 = new Test(1+9);
                        t1 = t2;
                }
        }

a) compiles, runs and prints " object number 10 created "
b) does not compiles
c) compiles, runs and prints " object number 1+9 created "
d) compiles, runs and prints " object number 10.0 created "

        public class Test {
                public static void main(String st[]){
                        Boolean b1 = new Boolean("true");
                        Boolean b2 = new Boolean(false);
                        System.out.println(b1);
                        System.out.println(b2);
                }

}

a) compiles, runs and prints
true
false
b) does not compile
c) compiles but runtime error
d) compiles, runs and does not print anything

        public class Test {
                public static void main(String st[]){
                        int i = -1>>>32;
                        System.out.println(i);
                }

}

a) compiles, runs and prints "0"
b) compiles, runs and prints "-1"
c) compiles, runs and prints "1"
d) compiles, runs and prints "-2"

        class MyFirstClass{
                public MyFirstClass(int k){
                        System.out.println("we are in MyFirstClass");
                }
        }

        public class Test extends MyFirstClass {

                public Test(){
                        System.out.println(",we are in Test");
                }

                public static void main(String st[]){
                        Test t1 = new Test();
                }
        }

a) compiles, runs and prints ", we are in Test we are in MyFirstClass"
b) compiles, runs and prints "we are in Test"
c) compiles, runs and prints "we are in MyFirstClass,we are in Test"
d) does not compile

        import java.awt.event.*;

        public class Test extends Frame implements ActionListener{

                private Button b1;
                private Button b2;
                private String message="message";

                public Test(){
                        setSize(300,300);
                        setLayout(new FlowLayout());
                        b1=new Button("b1");
                        b2=new Button("b2");
                        add(b1);
                        add(b2);
                        b1.addActionListener(this);
                        b2.addActionListener(this);
                        setVisible(true);
                }

                public void actionPerformed(ActionEvent ae){
                        if(ae.getSource()==b1) message=" b1 clicked";
                        if(ae.getSource()==b2) message=" b2 clicked";
                        repaint();
                }

                public void paint(Graphics g){
                        g.drawString(message,100,100);
                }

                public static void main(String st[]){
                        Test t1 = new Test();
                }
        }
 

a) "message"
b) "b1 clicked"
c) "b2 clicked"
d) "message b2 clicked"

        public class Test {

                public static void main(String st[]){
                        String s1 = "java";
                        String s2 = "java";
                        String s3 = "JAVA";
                        s2.toUpperCase();
                        s3.toUpperCase();
                        boolean b1 = s1==s2;
                        boolean b2 = s1==s3;
                        System.out.print(b1);
                        System.out.print(" "+b2);
                }
        }
 

a) compiles, runs and prints "true false"
b) compiles, runs and prints "true true"
c) compiles, runs and prints "false false"
d) compiles, runs and prints "false true"

        public class Test {

                public static void main(String st[]){
                        int j;
                        bb:
                        for(int i=1; i<10; i++){
                                for( j=1; j<3; j++){
                                        if(i>j) break bb;
                                        System.out.print(i+" ");
                                }
                        }
                }
        }
 

a) compiles, runs and prints "1 1 2 2"
b) compiles, runs and prints "1 1 1 1"
c) compiles, runs and prints "1 2"
d) compiles, runs and prints "1 1"

        public class Test {

                public static void main(String st[]){
                        byte b1 = 23;
                        byte b2 = 34;
                        System.out.print(b1*b2);
                }
}
 

a) does not compile
b) compiles, runs and prints "2334"
c) compiles, runs and prints "782"
d) compiles, runs and prints "b1b2"

        public class Test {

                public static void main(String st[]){
                        byte b1 = 23;
                        byte b2 = 34;
                        byte b3 = b1*b2;
                        System.out.print(b3);
                }
}
 

a) does not compile
b) compiles, runs and prints "2334"
c) compiles, runs and prints "782"
d) compiles, runs and prints "b1b2"

a)      interface Int1{
                void meth1();
                void meth2();
        }
        public class Test implements Int1{
        public void meth1(){}
        public void meth2(){}
        public static void main(String st[]){
                }
        }

b)      interface Int1{
                void meth1();
                void meth2();
        }
        public class Test implements Int1{
        void meth1(){}
        void meth2(){}
        public static void main(String st[]){
                }
        }

c)      interface Int1{
                void meth1(){};
                void meth2();
        }
        public class Test implements Int1{
                public void meth1(){}
                public void meth2(){}
                public static void main(String st[]){
                }
        }
d)      interface Int1{
                void meth1();
                void meth2();
        }
        public class Test extends Int1{
        public void meth1(){}
        public void meth2(){}
        public static void main(String st[]){
                }
        }
 
 

a)      class MyFirstClass {
                void meth1(){};
                void meth2(){};
        }

        abstract class MySecondClass {
                void meth4();
                void meth5();
        }
        public class Test extends MyFirstClass{
                public static void main(String st[]){
                }
        }

b)      class MyFirstClass {
                void meth1(){};
                void meth2(){};
        }

        abstract class MySecondClass {
                abstract void meth4();
                abstract void meth5();
        }
        public class Test extends MySecondClass{
                public static void main(String st[]){
                }
        }

c)      class MyFirstClass {
                void meth1(){};
                void meth2(){};
        }

        abstract class MySecondClass {
                abstract void meth4();
                abstract void meth5();
        }
        abstract public class Test extends MySecondClass{
                public static void main(String st[]){
                }
        }

d)      class MyFirstClass {
                void meth1(){};
                void meth2(){};
        }

        abstract class MySecondClass {
                abstract void meth4();
                bstract void meth5();
        }
        public class Test extends MyFirstClass{
                public static void main(String st[]){
                }
        }

Q16-The following program is in file Test.java, what would be the output
        of compiling and running this program ?
 

public class Test {
  public static void main(String st[]){
     Test t1 = new Test();
     t1.method1(5,0);
  }

  public void method1(int a, int b){
     try{
        int c = a/b;
        System.out.println("after division");
     } catch (ArithmeticException ae){System.out.println("Arithmetic Exception");}
       catch (Exception e){System.out.println("Exception");}
       finally {System.out.println("Finally");}

     System.out.println("after finally");

  }
}
 

a) compiles, runs and prints
                after division
                Arithmetic Exception
                Exception
                Finally
                after finally

b) compiles, runs and prints
                after division
                Arithmetic Exception
                Finally
                after finally
c) compiles, runs and prints
                Arithmetic Exception
                Finally
                after finally
d) compiles, runs and prints
                Arithmetic Exception
                Exception
                Finally
                after finally

public class Test {
  public static void main(String st[]){
     Test t1 = new Test();
     try{
     t1.method1(5,0);
     } catch (ArithmeticException ae){System.out.println("Arithmetic Exception");}
       catch (Exception e){System.out.println("Exception");}
       finally {System.out.println("Finally");}
  }

  public void method1(int a, int b){
        int c = a/b;
        System.out.println("after division");
  }
}
 

a) compiles, runs and prints
                after division
                Arithmetic Exception
                Exception
                Finally
                after finally

b) compiles, runs and prints
                after division
                Arithmetic Exception
                Finally
                after finally
c) compiles, runs and prints
                Arithmetic Exception
                Finally
                after finally
d) compiles, runs and prints
                Arithmetic Exception
                Finally

public class Test {

  public static void main(String st[]){
     Test t2 = new Test();
     t2.method2();
  }

  public void method2(){
     int x=1;
     boolean b1=true;
     boolean b2=false;
     if((b1&b2)&&(++x<4))   System.out.println("x="+x);
     if((!b1|b2)||(++x<4))  System.out.println("x="+x);
  }
}
 

a) does not compile.
b) compiles, runs and prints "x=2"
c) compiles, runs and prints "x=1"
d) compiles, runs and prints "x=3"

public class Test {

  public static void main(String st[]){
     Test t3 = new Test();
     t3.method2();
  }

  public void method2(){
     double x = - 99.5;
     System.out.println("output is ="+Math.abs(Math.ceil(Math.floor(x))));
  }
}
 

a) compiles, runs and prints "output is =100.0"
b) compiles, runs and prints "output is =99.5"
c) compiles, runs and prints "output is =100"
d) compiles, runs and prints "output is =-100.0"

import java.io.*;

1: public class Test {
2:   public static void main(String st[]) throws IOException{
3:     String f="file1.java";
4:     File f1 = new File(f);
5:     // here
6:  }
7: }
 

a) InputStream iout = new InputStream(f1);
b) InputStream iout = new FileInputStream(f1);
c) FileOutputStream iout = new FileOutputStream(f1);
d) Reader iout = new FileReader(f1);

public class Test {
   public int x = 99;
   private String s = "Hi";
   public void method1(){
      int x = 66;
      class MyClass{
         public float y = 45.9f;
         public void method2(){
            System.out.println("x = "+x);
         }
      }
      MyClass m = new MyClass();
      m.method2();
   }
   public static void main(String st[]){
     Test t1 = new Test();
     t1.method1();
   }
}
 

a) compiles, runs and prints "99"
b) compiles, runs and prints "66"
c) does not compile
d) compiles but develops a runtime error.

1: public class Test {
2:    public static void main(String st[]){
3:    String []s[] = {{"a","b"},{"c","d","e"}};
4:        // here
5:  }
6: }
 

a) System.out.println(s[0][1]);
b) System.out.println(s[0][2]);
c) System.out.println(s[1][2]);
d) System.out.println(s[1][3]);

Q23-Which of the statements would NOT compile ?

a) int x = (int)56L;
b) float f = 9.9999;
c) char c =(byte)23;
d) boolean b = False;

public class Test {
   public static void main(String st[]){
     int x = 7;
     int y = 8;
     int z = 2*x|y-1>>2;
     System.out.println("z="+z);
  }
}
 

a) does not compile.
b) compiles, runs and prints "z=14"
c) compiles, runs and prints "z=15"
d) compiles, runs and prints "z=16"

1: class MyFirstClass {
2:   public int x = 1;
3:   private float y = 3.4f;
4:   protected String s = "hello";
5:   private void meth1(){
6:      // here
7:   }
8: }
9: public class Test extends MyFirstClass{
10:   public void show(){
11:      System.out.println(y);
12:   }
13:   public static void main(String st[]){
14:      new Test().show();
15:  }
16: }
 

a) System.out.println(y);
b) System.out.println(x);
c) meth1();
d) System.out.println(s);

class MyFirstClass{
    public MyFirstClass(){
       System.out.println("Hi");
       show();
    }

    public void show(){
       System.out.println("in class MyFirstClass");
    }
}

public class Test extends MyFirstClass{
   public Test(){
      System.out.println("Hello");
   }
   public void show(){
      System.out.println("in class Test");
   }
   public static void main(String st[]){
      new Test();
  }
}

a) compiles, runs and prints
        Hello
        Hi
        in class MyFirstClass
b) compiles, runs and prints
        Hi
        Hello
        in class MyFirstClass
c) compiles, runs and prints
        Hi
        in class MyFirstClass
        Hello
d) compiles, runs and prints
        Hi
        in class Test
        Hello

public class Test {
   int x = 0;
   float f = 0.0f;
   public Test(int a, float b){
      this.x = a;
      this.f = b;
   }
   public static void main(String st[]){
      Test t1 = new Test(1,9.9f);
      Test t2 = new Test(2,8.8f);
      Test t3 = t1.swap(t1,t2);
      System.out.println(t1.x+"  "+t1.f);
      System.out.println(t3.x+"  "+t3.f);
  }
  public Test swap(Test t1, Test t2){
      Test te = t1;
      t1 = t2;
      t2 = te;
      Test t3 = new Test(0,0.0f);
      t3.x = t2.x;
      t3.f = t2.f;
      return t3;
}
}

a) compiles, runs and prints
        1  9.9
        1  9.9
b) compiles, runs and prints
        1  9.9
        0  0.0
c) compiles, runs and prints
        1  9.9
        2  8.8
d) compiles, runs and prints
        2  8.8
        2  8.8

a) paint
b) update
c) repaint
d) setVisible

a) +var
b) #var
c) $var
d) _9var

public class Test {
   public static void main(String st[]){
        String s1 = "JAVAIT";
        String s2 = "javaIT";
        String s3 = s2.toUpperCase();
        boolean b1 = s1.equals(s2);
        boolean b2 = s1.equalsIgnoreCase(s2);
        boolean b3 = s3.equals(s1);
        System.out.println(b1+"  "+b2+"  "+b3);
}
}

a) compiles, runs and prints "true  true  true"
b) compiles, runs and prints "false  true  false"
c) compiles, runs and prints "true  false  true"
d) compiles, runs and prints "false  true  true"

import java.awt.*;

public class Test extends Frame{
   public Test(){
      setSize(200,200);
   }
   public void paint(Graphics g){
      g.drawString("Maria",50,50);
   }
   public static void main(String st[]){
        new Test();
}
}

a) compiles, runs and a frame shows up with "Maria" printed
b) compiles, runs, but no frame shows up
c) does not compile
d) compiles but does not run

class PrintMess{
    synchronized public void show(String mess){
        try{
           Thread.sleep(1000);
        } catch (InterruptedException ie){}
        System.out.print(mess);
    }
}
class MyThread implements Runnable{
   String mess = null;
   PrintMess p = null;
   Thread t;
   public MyThread(PrintMess a, String b){
      p = a;
      mess = b;
      t = new Thread(this);
      t.start();
   }
   public void run(){
      for(int i=0; i<5; i++)
      p.show(mess);
   }
}
public class Test {
   public static void main(String st[]){
        PrintMess p = new PrintMess();
        MyThread m1 = new MyThread(p,"a");
        MyThread m2 = new MyThread(p,"b");
}
}

a) compiles, runs and prints "aaaaabbbbb"
b) compiles, runs and prints "ababababab"
c) compiles, runs and prints "bbbbbaaaaa"
d) compiles, runs and prints "baabbabbaa"

public class Test {
   public static void main(String st[]){
   l1:
   for(int i=4; i<=7; i++)
   switch(i){
        default:{System.out.println("default");}
        case 4: {System.out.println("case 4");}
        break;
        case 5: {System.out.println("case 5");} break l1;
        case 6: {System.out.println("case 6");}
        case 7: {System.out.println("case 7");}
        }
}
}

a) compiles, runs and prints "default case 4 "
b) compiles, runs and prints "default case 4 case 5"
c) compiles, runs and prints "case 4 case 5"
d) compiles, runs and prints "case 4 case 5 case 6 case 7"

public class Test {
   public static void main(String st[]){

      int x = 0;
      do {
         System.out.println("while");
         x = ++x + 1 + x++ ;
      }
        while(x<=8);
}
}

a) compiles, runs and prints "while while"
b) compiles, runs and prints "while while while"
c) does not compile
d) compiles but does not run

public class Test {
   public static void main(String st[]){

      for(int i=0; i<=1 ; i++)
         {//j++;
         for(int j=0; j<=3; j++)
            if(j>=2) break;
            System.out.print(i+""+j);
         }

   }
}

a) compiles, runs and prints "00011011"
b) compiles, runs and prints "0001"
c) compiles, runs and prints "0001101112"
d) does not compile

public class Test {
   public static void main(String st[]){
      int x = 1;
      int y = 2;
      System.out.println( x == y ? "x equals y" : " x not equal to y" );
}
}

a) compiles, runs and prints "x equals y"
b) compiles, runs and prints "x not equal to y"
c) does not compile
d) compiles, runs and prints "x == y ? "x equals y" : " x not equal to y"

public class Test {
   float f = 2.3f;
   long l = 234;
   public Test(float a, long b){
      f = a;
      l = b;
   }
   public static void main(String st[]){
      Test t1 = new Test(4.5f , 34);
      Test t2 = new Test(6.7f , 234);
      Test t3 = new Test(7.6f , 49);
      t2 = t1 = t3;
      System.out.println(t2.f +" "+ t2.l);
}
}

a) compiles, runs and prints "7.6 49"
b) compiles, runs and prints "6.7 234"
c) does not compile
d) compiles, runs and prints "4.5 34"

public class Test {
   public void meth1(int b, String s){
            System.out.println("meth1 int String");
   }
   public void meth1(long b, String s){
            System.out.println("meth1 long String");
   }
   public String meth1(long b, String s){
            System.out.println("meth1 long String + return ");
            return s;
   }
   public static void main(String st[]){
      new Test().meth1(2,"Hi");
}
}

a) does not compile
b) compiles, runs and prints "meth1 int String"
c) compiles, runs and prints "meth1 long String + return"
d) compiles, runs and prints "meth1 long String"

Related:

• Interview Questions in Core Java - Part Two
• Java Interview Questions
• Interview Questions in Core Java

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