Programming Questions |
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Q1)What is the o/p of following program? public class Question05 { public static void main(String[] args) { Question05Sub myref = new Question05Sub(); try{ myref.test(); }catch(IOException ioe){} } void test() throws IOException{ System.out.println("In Question05"); throw new IOException(); } } class Question05Sub extends Question05 { void test() { System.out.println("In Question05Sub"); } } a) In Question05 b) In Question05Sub c) Compilation error d) In Question05 In Question05Sub Answer
Answer is c. If the parent method throws a Checked Exception then the child class overriding it can throw same exception or unchecked exception or any subclass of the Exception thrown (in this case subclass of IOException)
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Q2) What is the o/p of following program? public class ThreadClass { public static void main(String[] args) { new ThreadClass().doSomething(); } public void doSomething(){ int i=5; Thread t = new Thread(new Runnable(){ public void run(){ for(int j=0;j<=i;j++){ System.out.print(" "+j); } } }); t.start(); } } a) Print 0,1,2,3,4 b) Print 1,2,3,4 c) Compilation error d) throws RunTimeException Answer
Answer is c, the local variable i cannot be accessed directly inside inner class. To make it accessible it should be declared as final.
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Q3)What is the o/p of following program? public class Parent { static { System.out.println("Inside Parent static"); } { System.out.println("Inside Parent init"); } public Parent(){ System.out.println("Parent Const"); } public static void main(String args[]){ new MyChild(); } } class MyChild extends Parent{ static { System.out.println("Inside Child static"); } { System.out.println("Inside Child init"); } public MyChild(){ System.out.println("Child Const"); } } a) Inside Parent static Inside Child static Inside Parent init Parent Const Inside Child init Child Const b) Inside Parent static Inside Child static Inside Parent init Inside Child init Parent Const Child Const c) Inside Parent static Inside Child static Inside Parent init Inside Child init Child Const Parent Const d) Inside Parent init Inside Child init Inside Parent static Inside Child static Child Const Parent Const Answer
Answer is a.
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Q4)What is the o/p of following program? public class Test { public static void main(String args[]){ int i = 132; short s = 15; byte b = (byte)i; int x = b + s; System.out.println(x); } } a) 147 b) -109 c) Compilation error d) Rutime error Answer
Answer is b.
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Q5)What is o/p of following program? public class Test { public static void main(String args[]){ int i = 132; List list = new ArrayList list.add(new Object()); list.add("Hi"); list.add(i); System.out.println(list.get(1)); } } a) Hi b)Compilation Error c) Runtime Error d) 132 Answer
Answer is a.
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Q6)Which of the o/p following program? public class StringTest { public static void main(String[] args) { String String = "String"; //line 1 int temp = 2; //line 2 Object:for(int main=0;main if(main>temp) //line 5 break Object; //line 6 } } } a) Prints S r n b) Prints t i g c) Compilation Error d) Prints t g Answer
Answer is a.
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| Q7) Select methods that correctly overload the following method byte bMethod(short i) throws Exception {...} a) int bMethod(int i) throws IOException{...} b) protected int bMethod(short s) throws FileNotFoundException{...} c) private String aMethod(byte b,short s) throws Exception{...} d) char bMethod(String s) throws RuntimeException{...} e) int bMethod(short sh){...} Answer
Answer is a,c,d.
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| Q8) What is o/p of following program? public class FinalVar { private int final i; public static void main(String args[]){ System.out.println(new FinalVar().i); } } a) 1 b) 0 c) RunTimeException occurs d) Compile time error 'i should be initialized' Answer
Answer is d.final variable need to be declared always even the default value should be mentioned explicitly.
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