Test de prueba para Examen de certificación

Name the keyword that makes a variable belong to a class, rather than being defined for each instance of the class. Select the one correct answer.

Which of the following are correct. Select the one correct answer.

. What is the result of compiling and running the following program.

public class Test {
public static void main (String[] args){
String str1 = "abc";
String str2 = "def";
String str3 = str1.concat(str2);

str1.concat(str2);
System.out.println(str1);
}
}

Assume that class A extends class B, which extends class C. Also all the three classes implement the method test(). How can a method in a class A invoke the test() method defined in class C (without creating a new instance of class C). Select the one correct answer.

Which keyword when applied on a method indicates that only one thread should execute the method at a time. Select the one correct answer.

Assuming the declaration String s = new String(“xyz”);
Which of the following statements would compile. Select the one correct answer.

What gets printed when the following code is compiled and run. Select the one correct answer.
public class test {
public static void main(String args[]) {
int i = 1;
do {
i--;
} while (i > 2);
System.out.println(i);
}
}

What all gets printed when the following program is compiled and run. Select the one correct answer.
public class test {
public static void main(String args[]) {
int i=0, j=2;
do {
i=++i;
j--;
} while(j>0);
System.out.println(i);
}
}

What all gets printed when the following program is compiled and run. Select the two correct answers.
public class test {
public static void main(String args[]) {
int i, j=1;
i = (j>1)?2:1;
switch(i) {
case 0: System.out.println(0); break;
case 1: System.out.println(1);
case 2: System.out.println(2); break;
case 3: System.out.println(3); break;
}
}
}

. Which of the following is correct? Select the correct answer.

What gets printed when the following code is compiled and run with the following command: java test 2
Select the one correct answer.
public class test {
public static void main(String args[]) {
Integer intObj=Integer.valueOf(args[args.length-1]);
int i = intObj.intValue();
if(args.length > 1)
System.out.println(i);
if(args.length > 0)
System.out.println(i - 1);
else
System.out.println(i - 2);
}
}

What is the default priority of a newly created thread.

What should be done to invoke the run() method on a thread for an object derived from the Thread class. Select the one correct answer.

Select the one most appropriate answer. What is the purpose of method parseInt defined in Integer class.

In implementing two classes Employee and Manager, such that each Manager is an Employee, what should be the relationship between these classes. Select the one correct answer.

What gets printed when the following program is compiled and run. Select the one correct answer.
public class incr {
public static void main(String args[]) {
int i , j;
i = j = 3;
int n = 2 * ++i;
int m = 2 * j++;
System.out.println(i + " " + j + " " + n + " " + m);
}
}

The class Hashtable is used to implement which collection interface. Select the one correct answer.

How many bytes are used to represent the primitive data type int in Java. Select the one correct answer.

What would happen when the following is compiled and executed. Select the one correct answer.
public class Compare {
public static void main(String args[]) {
int x = 10, y;
if(x < 10) y = 1;
if(x>= 10) y = 2;
System.out.println("y is " + y);
}
}

What happens when the following program is compiled and run. Select the one correct answer.
public class example {
int i[] = {0};
public static void main(String args[]) {
int i[] = {1};
change_i(i);
System.out.println(i[0]);
}
public static void change_i(int i[]) {
int j[] = {2};
i = j;
}
}

What is the minimum value of char type. Select the one correct answer.

What is the legal range of values for a variable declared as a byte. Select the one correct answer.

What would happen when the following is compiled and executed. Select the one correct answer
class example {
int x;
int y;
String name;
public static void main(String args[]) {
example pnt = new example();
System.out.println("pnt is " + pnt.name + " " + pnt.x + " " + pnt.y);
}
}

What would be the results of compiling and running the following class. Select the one correct answer.
class test {
public static void main() {
System.out.println("test");
}
}

. What happens when the following program is compiled and executed with the command – java test. Select the one correct answer.
class test {
public static void main(String args[]) {
if(args.length > 0)
System.out.println(args.length);
}
}

What is the result of compiling and running this program? Select the one correct answer.

public class test {
public static void main(String args[]) {
int i, j;
int k = 0;
j = 2;
k = j = i = 1;
System.out.println(k);
}
}