Year 2016
Q.no 11
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public class tu16Q11 { public static void main(String[] args) { int [] a={1,22,23,3,4,67,87,23,56,35,47,5,61,7,80,9,23,23,45,456,345,67,0,23,45,67,87,1,3,4}; for(int i=0;i<30;i++){ if(a[i]>16 &&a[i]<47){ System.out.println(a[i]); } } } } or /** * * @author bim study notes */ import java.util.*; public class ArrayDemo { public static void main(String[] args) { int arr[] = new int[30]; Random r = new Random(); int i; for(i=0;i<arr.length;i++){ int num = r.nextInt()%50; arr[i] = num; } for(i=0;i<arr.length;i++){ if(arr[i]>16&&arr[i]<47) System.out.print(arr[i]+" "); } } } |
Q.no 12 Create two classes ThreadA and ThreadB which implement Runnable interface. ThreadA displays all even numbers from 50 to 100 and ThreadB displays all odd numbers from 100 to 200. Define a main class which creates the objects of both the classes and displays the numbers as per the above mentioned specifications .
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class ThreadA implements Runnable{ public void run(){ int i; for(i=50;i<100;i++){ if(i%2==0){ System.out.println(i); } } } } class ThreadB implements Runnable{ public void run(){ int j; for(j=100;j<200;j++){ if(j%2==1){ System.out.println(j); } } } } public class tu16Q12 { public static void main(String[] args) { ThreadA t1=new ThreadA(); Thread objA=new Thread(t1); objA.start(); ThreadB t2=new ThreadB(); Thread objB=new Thread(t2); objB.start(); /** * * @author bim study notes */ } } |
13. Create an interface called Calculate which has methods int add(int x, int y) and diff(int x, int y) to perform addition and subtraction of numbers passed as arguments.Then define a class that implements interface calculate .
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interface Calculate{ int add(int x,int y); int diff(int x,int y); } class Mathematics implements Calculate{ @Override public int add(int x,int y) { int sum=x+y; System.out.println("The sum is:"+sum); return sum; } @Override public int diff(int x, int y) { int sub=x-y; System.out.println("The difference is:"+sub); return sub; } public static void main(String[] args) { Mathematics mth=new Mathematics(); mth.add(10, 30); mth.diff(10, 5); } } or interface Calculate{ int add(int x, int y); int diff(int x, int y); } class Calculator implements Calculate{ public int add(int x,int y){ return x+y; } public int diff(int x,int y){ return x-y; /** * * @author bim study notes */ } } public class CalculatorDemo { public static void main(String[] args) { Calculator c = new Calculator(); System.out.println("The sum of 4 and 5 is ="+c.add(4, 5)); System.out.println("The difference of 10 and 5 ="+c.diff(10, 5)); <strong> </strong> |
14. Define String array of size 4 and store name of 4 students. Then display the names of students whose name has character ‘t’
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/** * * @author bim study notes */ public class tu16Q14 { public static void main(String[] args) { String []name={"abc","ukutyy","ags","yasty"}; for(int i=0;i<4;i++){ if(name[i].contains("t")){ System.out.println(name[i]); } } } } <strong>or </strong>public class NameDemo { public static void main(String[] args) { String name[] = {"Sita","Gita","Ram","Kamala"}; for(int i=0;i<name.length;i++){ if(name[i].contains("t")) System.out.println(name[i]); } } } |
15. Write a program that displays content of folder database stored in d: drive.
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import java.io.File; public class DirList { public static void main(String[] args) { String dirname = “D:/database"; File f1 = new File(dirname); if(f1.isDirectory()){ String s[] = f1.list(); for(int i=0;i<s.length;i++){ File f = new File(dirname+ "/"+s[i]); if(f.isDirectory()){ System.out.println(s[i]+" is a directory"); } else System.out.println(s[i]+" is a file"); } } } } |
Group C
16: Explain dynamic polymorphism with example.
Runtime polymorphismor Dynamic Method Dispatchis a process in which a call to an overridden method is resolved at runtime rather than compile-time.In this process, an overridden method is called through the reference variable of a super class.The determination of the method to be called is based on the object being referred to by the reference variable.
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class Bike{ void run(){System.out.println("running");} } class Splender extends Bike{ void run(){System.out.println("running safely with 60km"); } } public class DymamicPolymorphismDemo { public static void main(String[] args) { Bike b; Splender s = new Splender(); Bike b1 = new Bike(); b = b1; b.run(); b = s; b.run(); } } /** * * @author bim study notes */ |
17. What is exception? Write a program to catch the ArrayIndexOutOfBoundsException.
An exception is an abnormal condition that arises in a code sequence at run time. In other words, an exception is a run time error.When an Exception occurs the normal flow of the program is disrupted and the program/Application terminates abnormally, which is not recommended, therefore these exceptions are to be handled.Some reasons that may cause exception to occur
- A user has entered invalid data.
- A file that needs to be opened cannot be found.
- A network connection has been lost in the middle of communications or the JVM has run out of memory.
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public class ArrayIndexOutOfBoundsExceptionDemo { public static void main(String[] args) { int arr[] = {3,4,5,6,1}; try{ for(int i=0;i<=arr.length;i++) System.out.print(arr[i]+" "); }catch(ArrayIndexOutOfBoundsException e){ System.out.println("Exception occurred "+e); } |
}
}