The document contains a list of 40 Java interview questions related to core Java, servlets, and JSP. The questions cover topics such as default array values, declaring and initializing arrays, Java keywords, if/else conditions, switch statements, loops, strings, wrappers, methods, threads, JDBC, servlet scopes, servlet lifecycle methods, differences between servlets and JSPs, implicit objects in JSP, and JSP directives.

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Java Interview Questions
(Core java, Servlets, JSP) Date:2012-10-19
Time:1:30 hrs
1) Which four options describe the correct default values for array elements of the types
indicated?
1)int -> 0 2)String -> "null" 3)Dog -> null
4)char -> 'u0000' 5)float -> 0.0f 6)boolean -> true
2) Which will legally declare, construct, and initialize an array?
1. int [] myList = {"1", "2", "3"};
2. int [] myList = (5, 8, 2);
3. int myList [] [] = {4,9,7,0};
4. int myList [] = {4, 3, 7};
3) Which is a reserved word in the Java programming language?
A. method B. native
C. subclasses D. reference
E. array
4) public void foo( boolean a, boolean b)
{
if( a )
{
System.out.println("A"); /* Line 5 */
}
else if(a && b) /* Line 7 */
{
System.out.println( "A && B");
}
else /* Line 11 */
{
if ( !b )
{
Java Interview Questions

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System.out.println( "notB") ;
}
else
{
System.out.println( "ELSE" ) ;
}
}
}
A. If a is true and b is true then the output is "A && B"
B. If a is true and b is false then the output is "notB"
C. If a is false and b is true then the output is "ELSE"
D. If a is false and b is false then the output is "ELSE"
5) public void test(int x)
{
int odd = 1;
if(odd) /* Line 4 */
{
System.out.println("odd");
}
else
{
System.out.println("even");
}
}
Which statement is true?
A. Compilation fails.
B. "odd" will always be output.
C. "even" will always be output.
D. "odd" will be output for odd values of x, and "even" for even values.
6) . What is the output when you execute the following code?
int i = 100;
switch (i) {
case 100:
System.out.println(i);
case 200:
System.out.println(i);
Java Interview Questions

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case 300:
System.out.println(i);
}
A) Nothing is printed B) Compile time error
C) The values 100,100,100 printed D) Only 100 is printed
7) . What is the result of compiling the following code?
public class Test {
public static void main ( String[] args) {
int value;
value = value + 1;
System.out.println(" The value is : " + value);
}}
A) Compile and runs with no output
B) Compiles and runs printing out "The value is 1"
C) Does not compile
D) Compiles but generates run time error
8) . What will happen when you attempt to compile and run the following code?
public class MyClass {
public static void main(String args[]) {
String s1 = new String("Test One");
String s2 = new String("Test One");
if ( s1== s2 ) {
System.out.println("Both are equal");
}
Boolean b = new Boolean(true);
Boolean b1 = new Boolean(false);
if ( b.equals(b1) ) {
System.out.println("These wrappers are equal");
}}}
A) Compile time error B)Runtime error.C)No output D)These wrappers are equal
9) . What is the result of the following code?
public class MyTest {
int x = 30;
public static void main(String args[]) {
int x = 20;
MyTest ta = new MyTest();
ta.Method(x);
System.out.println("The x value is " + x);
}
void Method(int y){
int x = y * y;
}}
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A)The x value is 20. B)The x value is 30. C)The x value is 400. D)The x value is 600.
10) . Which of the following places no constraints on the type of elements, order
of elements, or repetition of elements with in the collection.?
A) Collection B) collection C) Map D) Set
11) What will be the output of the program?
class PassS
{
public static void main(String [] args)
{
PassS p = new PassS();
p.start();
}
void start()
{
String s1 = "slip";
String s2 = fix(s1);
System.out.println(s1 + " " + s2);
}
String fix(String s1)
{
s1 = s1 + "stream";
System.out.print(s1 + " ");
return "stream";
}
}
A. slip stream
B. slipstream stream
C. stream slip stream
D. slipstream slip stream
12) What will be the output of the program?
class Test
{
public static void main(String [] args)
{
int x=20;
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String sup = (x < 15) ? "small" : (x < 22)? "tiny" : "huge";
System.out.println(sup);
}
}
A. small B. tiny
C. huge D. Compilation fails
13) What will be the output of the program?
class Test
{
public static void main(String [] args)
{
int x= 0;
int y= 0;
for (int z = 0; z < 5; z++)
{
if (( ++x > 2 ) && (++y > 2))
{
x++;
}
}
System.out.println(x + " " + y);
}
}
A. 52 B. 53
C. 63 D. 64
14) What will be the output of the program?
class Bitwise
{
public static void main(String [] args)
{
int x = 11 & 9;
int y = x ^ 3;
System.out.println( y | 12 );
}
}
A. 0 B. 7
C. 8 D. 14
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15) What will be the output of the program?
class SSBool
{
public static void main(String [] args)
{
boolean b1 = true;
boolean b2 = false;
boolean b3 = true;
if ( b1 & b2 | b2 & b3 | b2 ) /* Line 8 */
System.out.print("ok ");
if ( b1 & b2 | b2 & b3 | b2 | b1 ) /*Line 10*/
System.out.println("dokey");
}
}
A. ok
B. dokey
C. ok dokey
D. No output is produced
E. Compilation error
16) What will be the output of the program?
class SC2
{
public static void main(String [] args)
{
SC2 s = new SC2();
s.start();
}
void start()
{
int a = 3;
int b = 4;
System.out.print(" " + 7 + 2 + " ");
System.out.print(a + b);
System.out.print(" " + a + b + " ");
System.out.print(foo() + a + b + " ");
System.out.println(a + b + foo());
}
String foo()
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{
return "foo";
}
}
A. 9 7 7 foo 7 7foo
B. 72 34 34 foo34 34foo
C. 9 7 7 foo34 34foo
D. 72 7 34 foo34 7foo
17) What will be the output of the program?
class Test
{
static int s;
public static void main(String [] args)
{
Test p = new Test();
p.start();
System.out.println(s);
}
void start()
{
int x = 7;
twice(x);
System.out.print(x + " ");
}
void twice(int x)
{
x = x*2;
s = x;
}
}
A. 77 B. 7 14
C. 14 0 D. 14 14
18) What are all the methods available in the Thread class?
1.isAlive() 2.join() 3.resume() 4.suspend() 5.stop() 6.start() 7.sleep() 8.destroy()
19) Which are keywords in Java?
a) NULL b) sizeof c) friend d) extends e) synchronized
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20) The Java source code can be created in a Notepad editor.
a)True b) False
21) Choose correct ansewrs
1. Servlet is a Java technology based Web component.
2. Servlet servlets are platform-independent
3. Servlet has run on Web server which has a containers
4. Servlets interact with Web clients via a request/response using HTTP protocol.
A.1,2,3,4 B.1,2,3 C.1,3,4 D.None
22) Which of the following are interface?
1.ServletContext
2.Servlet
3.GenericServlet
4.HttpServlet
A.1,2,3,4 B,1,2 C.1,3,4 D.1,4
23) Which of the following are class?
1.ServletContext
2.Servlet
3.GenericServlet
4.HttpServlet
A.1,2,3,4 B,1,2 C.3,4 D.1,4
24) Which of the following methods are main methods in life cycle of servlet?
1.init()
2 .service()
3.destroy()
4.srop()
5.wait()
A.1,2,3,4,5 B,1,2,3 C.3,4,5 D.1,4,5
25) init(),service() and destroy()methods are define in
1.javax.servlet.Servlet interface
2.javax.servlet.ServletHttp class
3.javax.servlet.ServletRequest interface
4.javax.servlet.ServletResponse interface
A.1,2,3,4,5 B,1 C.3,4,5 D.1,4,5
26) Int init() ,.service() and destroy() methods which methods are call only once at life cycle
of servlets
1.init()
2.service()
3.destroy()
A.1,2,3 B,1,3 C.2 D.None
27) Which JDBC driver Type(s) is(are) the JDBC-ODBC bridge?
A. Type 1
B. Type 2
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C. Type 3
D. Type 4
28) JDBC stands for:
A. Java Database Connectivity
B. Java Database Components
C. Java Database Control
D. None of the above is correct
29) What are the scopes in Servelts?
1) Page 2) request 3) response 4) session 5) application
30) What are the scopes in JSP?
1) Page 2) request 3) response 4) session 5) application
31) What are the implicit objects in jsp?
32) What is the difference between Difference between doGet() and doPost()?
33) What is the difference between HttpServlet and GenericServlet?
34) Explain the directory structure of a web application.
35) What is a output comment?
36) What is a Hidden comment?
37) What is a Expression?
38) What is a Declaration?
39) What is a Scriptlet?
40) Explain the life-cycle mehtods in JSP?
Java Interview Questions