Java Programming Fundamentals and Advanced Concepts

Question 1 Multiple Choice (Single Answer)

class c1 { public void m1() { System.out.println("m1 method in C1 class"); } } class c2 { public c1 m1() { return new c1(){ public void m1() { System.out.println("m1 mehod in anonymous class"); }};} public static void main(String a[]) { c1 ob1 =new c2().m1(); ob1.m1(); }}

prints m1 method in C1 class
prints m1 method in anonumous class
compile time error
Runtime error
none of the above

Question 2 Multiple Choice (Single Answer)

What is the output for the below code ? class A implements Runnable{ public void run(){ System.out.println(Thread.currentThread().getName()); } } public class Test { public static void main(String... args) { A a = new A(); Thread t = new Thread(a); Thread t1 = new Thread(a); t.setName("t"); t1.setName("t1"); t.setPriority(10); t1.setPriority(-3); t.start(); t1.start(); } }

t t1
t1 t
t t
Compilation succeed but Runtime Exception

Question 3 Multiple Choice (Single Answer)

What is the output for the below code ? public class B { public String getCountryName(){ return "USA"; } public StringBuffer getCountryName(){ StringBuffer sb = new StringBuffer(); sb.append("UK"); return sb; } public static void main(String[] args){ B b = new B(); System.out.println(b.getCountryName().toString()); } }

Compile with error
USA
UK
Runtime Exception

Question 4 Multiple Choice (Single Answer)

What is the output for the below code ?import java.util.regex.Matcher;import java.util.regex.Pattern;public class Test { public static void main(String... args) { Pattern p = Pattern.compile("a*b"); Matcher m = p.matcher("b"); boolean b = m.matches(); System.out.println(b); }}

true
Compile Error
false
b

Question 5 Multiple Choice (Single Answer)

What is the output for the below code ? public class A { public A() { System.out.println("A"); } } public class B extends A implements Serializable { public B() { System.out.println("B"); } } public class Test { public static void main(String... args) throws Exception { B b = new B(); ObjectOutputStream save = new ObjectOutputStream(new FileOutputStream("datafile")); save.writeObject(b); save.flush(); ObjectInputStream restore = new ObjectInputStream(new FileInputStream("datafile")); B z = (B) restore.readObject(); } }

A B A
A B A B
B B
A B

Question 6 Multiple Choice (Single Answer)

public class Question {  public static void main(String args[])  {  	int i=10;  	System.out.println("i="+++i);  }

i=0
i=11
invalid argument to operation
none

Question 7 Multiple Choice (Single Answer)

public class Question { public static void main(String args[]) { int x=010; System.out.print("X="+x); } }

X=8
X=10
X=11
None

Question 8 Multiple Choice (Single Answer)

public class Question { public static void main(String args[]) { int x=y=10; y=12; System.out.print(x+"&"+y); } }

10 & 12
10 & 10
Compile Time Error
None

Question 9 Multiple Choice (Single Answer)

public class e { public static void main(String args[]) { int i=3,j=2; System.out.print("i|j="+ (i|j)); } }

i | j = 3
i | j = 2
Compile Time Error
None

Question 10 Multiple Choice (Single Answer)

public class Question { public static void main(String args[]) { int x=0x10; System.out.print("X="+x); } }

X=10
X=16
X=0
Compile Time Error

Question 11 Multiple Choice (Single Answer)

Please dont Try this Question... Try Next One.... If you attend others, you will get to know the answer of this question. Questions: 1. 1. public class Question { Public static void main(String args[]) { int i=10; System.out.println("i="+++i); } 2. public class Question { public static void main(String args[]) { int x=010; System.out.print("X="+x); } } 3. public class Question { public static void main(String args[]) { int x=y=10; y=12; System.out.print(x+"&"+y); } } 4. public class Question{ public static void main(String args[]) { int i=3,j=2; System.out.print("i|j="+ (i|j)); } } 5. public class Question { public static void main(String args[]) { int x=0x10; System.out.print("X="+x); } } Answers: 1. System.out.println("i="+++i); Must be as a System.out.println("i="+ ++i); “Space between operators” 2. int x=010; In this statement, compile will take it as a OCTAL NUMBER. So OCTAL(10)=DECIMAL(8) 3. int x=y=10; In this statement, We are using y without declaring it. So will cause Compile Time Error. 4. 3 ? 1 1 2 ? 1 0 ------------------ (OR) 3 ? 1 1 5. int x=0x10; In the above statement, Compile will take it as a HEXA DECIMAL. So. HEXA(10) ? DECIMAL(16)

I gave
Questions and
Answers
in this question.

Question 12 Multiple Choice (Single Answer)

Which of the following class among these are synchronized?

StringBuilder
StringBuffer
Both (1) and (2)
None of the above

Question 13 Multiple Choice (Single Answer)

String s = "India";String s2 = s;s.concat (” is a nation.”);System.out.println(s);

India
India is a nation.
is a nation.
None of the above.

Question 14 True/False

Is String class final?

True
False

Question 15 Multiple Choice (Single Answer)

What is the output of following.

public static void main(String[]  args) {
    final int b=3;
    byte c=b/2;
    System.out.println("c="+c);
}

Runtime Exception
1.5
1
CompileTimeError

Question 16 Multiple Choice (Multiple Answers)

What is the output of following.

public static void main(String[]  args) {
    String s1="prasad";
    String s2="Ram";
    s1.concat(s2);
    System.out.println("c="+s1);
}

Ram
prasad
RamPrasad
PrasadRam

Question 17 Multiple Choice (Multiple Answers)

What is the output of following.

public static void main(String[]  args) {
    String s1="sanjay";
    String s2="sanjay";             
    System.out.println("c="+s1==s2);
}

prasad
true
false
compileTime Error

Question 18 Multiple Choice (Multiple Answers)

What is the output of following.

public static void main(String[]  args) {
    System.out.println("c="+args.length());
}

2
compileTimeError
1
RuntimeException