1).Emma is writing a program, where she needs to convert a collection to an arraylist Choose the correct option to help her.
Option:
a)ArrayList newList=srcCollection.stream().collect(toCollection(ArrayLists::new));
b)ArrayList<syn> newList= srcCollection.stream().collect(toCollection(ArrayList::new));
c)ArrayList <syn> newList =Collection.stream().collect(toCollection(ArrayList::new));
d)ArrayList <syn>newList= srcCollection.stream().collect (Collection(ArrayList::new));
Answer:-b
2) What will be the output of the following Java code?
public class Main {
public static void main(String[] args) {
int n=10;
int sum = 0;
for (int i = 0; i < n; i++) {
for (int j = 1; j < n; j++) {
sum + =i + j;
}
}
System.out.println(sum);
}
}
Option:
a)330
b)660
c)495
d)990
Answer:-c)495
3).class ImmutableString{
public static void main(String args[]){
String str=kate”;
str.concat(” Williams”);
System.out.println(str);
}
}
Predict the output?
Options:-
a).kate
b).Kate Williams
c).null
d).comptation error
Answer:-b).Kate Williams
4).Find the output of the code below:
class multithread
{
public static void main(String args[])
{
Thread t = Thread.currentThread();
System.out.println(t);
}
}
Options:-
a)Thread[5,main]
b)Thread[main, 5, main]
c)Thread[main 0]
d)Thread [main 5]
Answer:-b)Thread[main, 5, main]
5).Which of the following are true statements about serialization in Java?
(Choose two options)
Answer
Please choose all correct answers
a)The Senalizable interface declares the serialize() method
b).Senakizable is a functional interface
c).All threads are serializable
d).Deserialization is the process of turning a serialized stream back into an object.
e).An object can be serialized only if it implements the Serializable interface and contains instance variables that are serializable or marked transient
f)objects of final classes cannot be senalized
Answer:-(d) and (e)
6)In a Java assignment, the student is using a switch statement as given below
String alpha=”a”
switch(a) {
. .
. . .
}
The above code segment would not run for
Answer
Please choose a correct answer.
1)Java 5
2)Java 6
3)Java 7
4)Both 1 and 2
Answer:-4)Both 1 and 2
7)What will be the output of the code below?
public class MyThread extends Thread {
public void run() {
System.out.println(this.getName());
}
public static void main(String args[]) {
MyThread thread1 =new MyThread();
MyThread thread2=new MyThread();
thread1.start();
thread2.start();
}
}
1).Thread-0
Thread-1
2).Thread 1
Thread2
3).Thread 0
Thread 1
4)Thread0
Thread1
Answer :-
1).Thread-0
Thread-1
8)What will be the output of the following Java code?
public class Main {
public static void main(String[] args) {
int n=5;
int s=0;
for (int i=0; i < n; i++) {
for (int j =1; j < n; j++) {
for (int k=j; k < n; k++) {
s++;
}
}
}
System.out.println(s);
}
}
Options:-
1)15
2)35
3)70
4)125
Answer:-2)35
9) Which of the following is a valid identifier?
Answer
Please choose a correct answer.
1)DoSelect labs
2)2way
3)$_
4)new
5)default
Answer:-3)$_
10)When an application starts, only a single thread runs.
This thread is known as?
Answer
Please choose a correct answer.
1)Centre Thread
2)Priority Thread
3)First Thread
4)Main Thread
Answer:-4)Main Thread