Advanced
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Java Interview Questions Please go through important Java Interview Questions, solve them if you can, share it with your friends and save as bookmark for future reference! Java Interview Questions: Wh...
Advanced
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Java is used as one of the top web development programming language, it provides both flexibility and security hence the most popular programming language among the industry leaders, businesses and go...
Advanced
632 views
1 How could Java classes direct program messages to the system console, but error messages, say to a file? The class System has a variable out that represents the standard output, and the variable err...
Intermediate
578 views
1 If Runnable interface is better than Thread class, than why we are using Thread class? What is the need for Thread class? 2. Why we are calling System.gc() method to garbage collection of unused obj...
Advanced
458 views
1 How EJB Invocation happens? - Retrieve Home Object reference from Naming Service via JNDI. Retu Home Object reference to the client. Create me a new EJB Object through Home Object interface. Create ...
Advanced
400 views
The Following are Java/J2EE Interview Questions 1. What is Jakarta Struts Framework? - Jakarta Struts is open source implementation of MVC (Model-View-Controller) patte for the development of web base...
Intermediate
352 views
Agile Java job Interview Questions , a user submitted / interview experience direct from the desk of job interview. These Questions how ever not exactly how they appeared but have been recalled from t...
Advanced
154 views
Java Garbage Collection Architecture Mode JVMs use automatic memory management based on the Weak Generational Hypothesis : most allocated objects become unreachable shortly after creation (infant mort...
Advanced
132 views
What is the difference between procedural and object-oriented programs? - a) In procedural program, programming logic follows certain procedures and the instructions are executed one after another. In...
Advanced
5 views
The JVM Memory Structure is divided into: Heap Memory: Shared among all threads, storing object instances. Divided into Young Generation (Eden space, Survivor spaces S0/S1) and Old Generation (Tenured...
Easy
5 views
For objects, == compares reference identity, while equals can compare logical content according to the class implementation. String overrides equals to compare character sequences. Interning may make ...
Medium
5 views
try-with-resources closes objects implementing AutoCloseable when the scope exits, including when the body throws. Resources close in reverse declaration order. If the body throws and closing also thr...
Medium
5 views
Use an interface to define a capability that unrelated classes can implement, such as a payment gateway contract. Use an abstract class when implementations genuinely share state, construction rules, ...
Intermediate
4 views
In Java, a HashMap works on the principle of hashing. It internally uses an array of Node<K,V> buckets. When put(key, value) is called: The key's hashCode() is computed, then spread via an inter...
Beginner
4 views
String: Immutable object stored in the String Constant Pool . Any modification (e.g. concatenation) instantiates a new String object on the heap, resulting in memory fragmentation during frequent stri...
Medium
4 views
HashMap uses a key’s hash code to locate a bucket and equality to identify the matching key. If two equal objects produce different hash codes, lookup may search the wrong bucket. Equal objects must t...
Medium
4 views
volatile provides visibility and ordering guarantees for accesses to the field, but increment is a read-modify-write sequence. Two threads can read the same value and both write the same incremented r...
Easy
3 views
Its externally observable state cannot change after construction. Use private fields, initialize them fully, avoid mutating methods, and prevent uncontrolled subclass behavior where necessary. A final...