The ultimate guide to Java interviews with 300+ real-world questions and answers. Get interview-ready in just a few hours with strategies developed by FAANG engineers.

It’s very common to have interviews testing your knowledge of a programming language you claim to be an expert in.

If you've got an interview coming up on Java soon and need to get up to speed, this is the ideal course for you. You'll refresh your memory on everything from the basics to more advanced functionality you’re likely to be asked about. Even if you're using Java every day, you may not have been exposed to parts of it in some time, so it's always useful to make sure you're updated.

This course features more than 300 of the most commonly asked core Java interview questions that you're likely to face as an experienced software engineer. You'll get to explore questions by topic, as well as see detailed answers for each one, and plenty of live code examples where relevant. Get started today.

The Java Interview Handbook: 300+ Interview Questions

<div class="card">
   # Question # 1
    <div class="qtn">
        <p>Can String objects be modified after creation?</p>
    </div>
    <div class="ans">
        <p>No. <span class="hi-yl-b">Strings in Java are immutable and can't be changed once created.</p>
</div>
</div>


<div class="card">
   # Question # 2
    <div class="qtn">
        <p>Explain the difference between <code class="clazz">StringBuilder</code> and <code class="clazz">StringBuffer</code>?</p>
    </div>
  <div class="ans">
        <p>Java provides two utility classes for String manipulations – StringBuffer and StringBuilder.
<code class="clazz">StringBuffer</code> and <code class="clazz">StringBuilder</code> are mutable classes. StringBuffer operations are thread-safe and synchronized whereas StringBuilder operations are not thread-safe. So in a multi-threaded environment, we should use <code class="clazz">StringBuffer</code> but in the single-threaded environment, we should use <code class="clazz">StringBuilder</code>.
StringBuilder's performance is faster than StringBuffer's because of no overhead of synchronization.</p>
</div>

</div>


<div>
   # Question # 1
    <div>
        <p>Can String objects be modified after creation?</p>
    </div>
    <div>
        <p>No. <span>Strings in Java are immutable and can't be changed once created.</p>
</div>
</div>


<div>
   # Question # 2
    <div>
        <p>Explain the difference between <code>StringBuilder</code> and <code>StringBuffer</code>?</p>
    </div>
  <div>
        <p>Java provides two utility classes for String manipulations – StringBuffer and StringBuilder.
<code>StringBuffer</code> and <code>StringBuilder</code> are mutable classes. StringBuffer operations are thread-safe and synchronized whereas StringBuilder operations are not thread-safe. So in a multi-threaded environment, we should use <code>StringBuffer</code> but in the single-threaded environment, we should use <code>StringBuilder</code>.
StringBuilder's performance is faster than StringBuffer's because of no overhead of synchronization.</p>
</div>

</div>


This lesson discusses String interview questions in Java.

Java Ecosystem

Methods

Classes

Interfaces

Inheritance

Lambda Expressions

Generics

Multi-Threading

Memory Management

Collections

Exceptions

Reflection

Serialization

Miscellaneous Topics

Java in Practice

Patterns

The End

Strings

Question # 1

Question # 2