Java Programming - Level 2

The keyword "class" is used to make a class in programming. A class is a blueprint or template for creating objects, and it defines the properties and behaviors that an object of that class will have. In many programming languages, including Python, "class" is the keyword used to define a new class. Therefore, the correct answer is "class".

Explanation: this keyword can be used inside any method to refer to the current object. this is always a reference to the object on which the method was invoked.

The correct answer is charAt(). The charAt() method is used to obtain the character at a specified index in a String. It takes an index as a parameter and returns the character at that index.

Explanation: Operator new must be succeeded by array type and array size.

Explanation: operator + is used to concatenate strings, Example String s = “i ” + “like ” + “java”; String s contains “I like java”.

Explanation: Byte occupies 8 bits in memory. Its range is from -128 to 127.

Explanation: A variable can be declared final, doing so prevents its content from being modified. Final variables must be initialized when it is declared.

The correct answer is Runnable. The Thread class in Java implements the Runnable interface. This interface provides a way to define a task that can be executed concurrently by multiple threads. The Runnable interface has a single method called run(), which contains the code that will be executed when the thread is started. By implementing the Runnable interface, the Thread class can be used to create and control threads in Java.

Explanation: AWT stands for Abstract Window Toolkit, it is used by applets to interact with the user.

Explanation: All relational operators return a boolean value ie. true and false.

Explanation: The controlling condition of ternary operator must evaluate to boolean.

In object-oriented programming, overloading refers to the ability to define multiple methods or constructors with the same name but different parameters. This allows for flexibility and convenience when working with different data types or varying numbers of arguments. Therefore, both methods and constructors can be overloaded. By overloading methods or constructors, developers can create more versatile and reusable code.

Explanation: Packages are both naming and visibility control mechanism. We can define a class inside a package which is not accessible by code outside the package.

Explanation: Unary not operator, ~, inverts all of the bits of its operand in binary representation.

Explanation: Data type long literals are appended by an upper or lowercase L.

The keyword "static" is used to access members of a class before an object of that class is created. Static members belong to the class itself rather than to any specific instance of the class. They can be accessed using the class name followed by the member name, without the need for an object to be created. This allows for the use of class variables and methods without the need to instantiate an object of the class.

The correct answer is "public prototype( )". This is the prototype of the default constructor of the class. The "public" keyword indicates that the constructor is accessible from any other class. The "prototype" keyword is the name of the constructor, and the empty parentheses indicate that it does not take any parameters.

Explanation: Unicode defines fully international character set that can represent all the characters found in all human languages. Its range is from 0 to 65536.

Operator ++ increases value of variable by 1. x = x + 1 can also be written in shorthand form as x += 1. Also x =+ 1 will set the value of x to 1.

Serialization and deserialization occur automatically by java runtime system, Garbage collection also occur automatically but is done by CPU or the operating system not by the java runtime system.