Core Java - Interview Questions and Answers for 'Java.lang' | Search Interview Question

Core Java - Interview Questions and Answers for 'Java.lang' - 5 question(s) found - Order By Newest

Very frequently asked in HCL Tech ( Based of 4 inputs )

Q1. Write a Program to reverse a string iteratively and recursively

Ans. Using String method -

new StringBuffer(str).reverse().toString();

Iterative -

Strategy - Loop through each character of a String from last to first and append the character to StringBuilder / StringBuffer

public static String getReverseString(String str){
StringBuffer strBuffer = new StringBuffer(str.length);
for(int counter=str.length -1 ; counter>=0;counter--){
strBuffer.append(str.charAt(counter));
}
return strBuffer;
}

Recursive -

Strategy - Call the method with substring starting from 2nd character recursively till we have just 1 character.

public static String getReverseString(String str){
if(str.length <= 1){
return str;
}
return (getReverseString(str.subString(1)) + str.charAt(0);
}

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Q2. Do we need to import java.lang package ?

Core Java

Ans. No, It is loaded by default by the JVM.

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Q3. Name few classes that are part of java.lang package ?

Ans. http://www.buggybread.com/2015/01/java-javalang-classes-and-interfaces.html

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Rarely asked as it was introduced with Java 8.

Q4. Name few java.lang classes introduced with Java 8 ?

Core Java

Ans. http://www.buggybread.com/2015/01/migrating-to-java-8-new-classes.html

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Q5. Which java package is loaded by default and hence doesn't require an explicit import statement ?

Core Java

Ans. java.lang

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