What is the purpose of the Runtime class?
Ans : The purpose of the Runtime class is to provide access to the Java runtime system.

What is the purpose of the System class?
Ans : The purpose of the System class is to provide access to system resources.

Which class is extended by all other classes?
Ans : Object class is extended by all other classes.

Which class can be used to obtain design information about an object?
Ans : The Class class can be used to obtain information about an object’s design.

Which method is used to calculate the absolute value of a number?
Ans : abs( ) method.

What are E and PI?
Ans : E is the base of the natural logarithm and PI is the mathematical value pi.