JAVA TECHNICAL QUESTION & ANSWERS FOR INTERVIEW PART - I

Summary

The video script provides an in-depth overview of Java, discussing its origins, features, and core concepts. It starts by highlighting James Gosling as the father of Java and explains Java's development by Sun Microsystems in 1991. Key features such as portability, security, dynamic loading, and multi-threading are covered, alongside concepts like platform independence, class, object, method, encapsulation, inheritance, and polymorphism. The script also touches on Java's file structure, bytecode interpretation by the JVM, and the significance of primitive and non-primitive data types in Java programming.

Takeaways

• 👨‍💻 The father of Java is James Gosling, a Canadian computer scientist, who developed the language at Sun Microsystems.
• 📅 Java was first developed in 1991, with its public release in May 1995.
• 🚀 Java offers several key features such as being simple, portable, secure, dynamic, multi-threaded, object-oriented, and platform-independent.
• 📦 Java's portability is due to its 'Write Once, Run Anywhere' capability, allowing applications to run on any operating system with a Java Development Kit (JDK).
• 🛡️ Java is secure because it runs inside a virtual machine called the sandbox, restricting access to system resources and preventing malicious code.
• ♻️ Garbage collection in Java automatically manages memory, preventing memory leaks by clearing unused objects.
• 🧵 Java supports multi-threading, enabling parallel execution of multiple tasks, which improves application performance and CPU utilization.
• 🏛️ Java is platform-independent, meaning Java applications can run on different operating systems without modifying the code, as long as they have the Java Virtual Machine (JVM).
• 🔍 Java’s class structure acts as a blueprint for creating objects, encapsulating properties (instance variables) and behaviors (methods).
• 📂 Non-primitive data types in Java include classes, interfaces, strings, and arrays, as opposed to primitive types like int, float, and boolean.

Q & A

Who is considered the father of Java?

James Gosling, a Canadian computer scientist, is called the father of Java. He is best known as the founder and lead designer behind the Java programming language, born on May 19, 1955.

In which year was Java first developed?

Java was first developed in 1991, and the first public release was in May 1995.

Which company developed the Java programming language?

Java was developed by Sun Microsystems.

What are some key features of Java?

Key features of Java include being simple, portable, secure, dynamic, interpreted, multi-threaded, distributed, object-oriented, platform-independent, architecture-neutral, and offering high performance.

Why is Java considered a portable language?

Java is considered portable because it allows developers to write code once and run it on any operating system that supports Java. This is due to its platform-independent nature and the concept of 'write once, run anywhere.'

How does Java ensure security?

Java ensures security through several mechanisms: running programs inside a virtual machine (sandbox), avoiding explicit pointers, using garbage collection to prevent memory leakage, bytecode verification, the Java security package for implementing custom security, and runtime security checks via the Security Manager class.

What is meant by Java being 'dynamic'?

Java is dynamic because it supports dynamic loading of classes at runtime and allows interaction with native languages like C and C++. Java dynamically allocates memory and performs garbage collection during runtime.

What is the role of the Java interpreter (JVM)?

The Java interpreter, or Java Virtual Machine (JVM), converts bytecode (generated after compilation) into machine code. The JVM enables platform independence by interpreting bytecode into machine-specific code.

What is multi-threading in Java?

Multi-threading in Java allows for the concurrent execution of multiple threads, where each thread runs a set of statements independently. This improves application performance by allowing tasks to be processed simultaneously, maximizing CPU and memory utilization.

What does it mean that Java is platform-independent?

Java is platform-independent, meaning that a Java program can run on any operating system with a Java Virtual Machine (JVM). The same bytecode generated after compilation can be executed on different platforms without needing to modify the source code.