Simplify360 Java Developer Interview Questions and Answers

Java is a high-level programming language known for its portability, security, and object-oriented features.

• Java is platform-independent, meaning it can run on any device with a Java Virtual Machine (JVM).

• It is object-oriented, allowing for modular and reusable code.

• Java is known for its security features, such as sandboxing and encryption.

• Popular frameworks and libraries like Spring and Hibernate are commonly used in

Immutable class in Java cannot be modified after creation, ensuring data integrity.

• Make the class final so it cannot be extended

• Make all fields private and final so they cannot be modified

• Do not provide setter methods, only getter methods to access the fields

• If the class contains mutable objects, make sure to return a deep copy of them in getter methods

The question is asking to create a class with certain restrictions like being final, having private and final fields, and no setter methods.

• Declare the class as final to prevent it from being subclassed.

• Make all fields private and final to ensure encapsulation and immutability.

• Provide no setter methods to enforce read-only access to the fields.

The static keyword in Java is used to create class-level variables and methods that can be accessed without creating an instance of the class.

• Static variables are shared among all instances of a class.

• Static methods can be called without creating an instance of the class.

• Static blocks are used to initialize static variables.

• Static keyword can also be used to create static nested classes.

In Java, == compares memory addresses while .equals() compares the actual content of objects.

• == compares memory addresses of objects, while .equals() compares the actual content of objects.

• == is used to compare primitive data types, while .equals() is used to compare objects.

• Example: String str1 = new String("hello"); String str2 = new String("hello"); str1 == str2 will be false, but str1.equals(str2) will be true.

In Java, == compares object references, while .equals() compares object values.

• Use == to compare if two object references point to the same memory location.

• Use .equals() to compare if two objects have the same values.

• Example: String str1 = new String("hello"); String str2 = new String("hello"); str1 == str2 will be false, but str1.equals(str2) will be true.

No, a Java class cannot extend multiple classes.

• Java does not support multiple inheritance for classes.

• A class can only extend one other class, but can implement multiple interfaces.

• Example: class MyClass extends ParentClass implements Interface1, Interface2

The size of an int in Java is 4 bytes.

• An int in Java is a 32-bit signed integer.

• It can hold values ranging from -2,147,483,648 to 2,147,483,647.

• The size of an int is fixed at 4 bytes on all platforms.

Yes, the size of an int in Java is indeed 4 bytes (32 bits).

• An int in Java can hold values ranging from -2,147,483,648 to 2,147,483,647.

• The size of an int can be confirmed using the 'Integer.SIZE' constant in Java.

• Using 'Integer.BYTES' will give the size of an int in bytes.

The default value of an int in Java is 0.

• In Java, when an int variable is declared but not initialized, it is automatically assigned the default value of 0.

• For example, int num; // num is assigned the default value of 0.

Yes, the default value of an int in Java is 0.

• In Java, when an int variable is declared but not initialized, it will have a default value of 0.

• For example, int num; will have a default value of 0.

• This default value is assigned by the Java Virtual Machine (JVM) when memory is allocated for the variable.