8/2/2019 Bt0074 Unit 2 Faqs

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Frequently Asked Questions

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Subject Name: OOPS with Java Subject Code: BT0074

Unit 2: Java BasicsBalasubramani R

Assistant ProfessorDept. of ITQ1: What do you mean by Java keywords?

A1: Keywords are special words that are of significance to the Java compiler. There are 48

reserved keywords currently defined in the Java language. These keywords combined

with the syntax of the operators and separators, form the definition of the Java language.

These keywords cannot be used as names for a variable, class, or method.

Q2: How do Java programs run?

A2: The concept of write once, run anywhere is possible in Java. The Java program can be

compiled on any platform having a Java compiler. The resulting bytecode can then be run

on any machine. The machine should have a Java platform to run Java code. Javaplatform consists of Java Virtual Machine (JVM) and a package known as Java

Application Programming Interface (Java API).

Q3: What are the various primitive data types in Java?

A3: Primitive data types are the data types that are built into the Java language. The Java

compiler holds detailed instructions on each legal operation the data type supports. There

are eight primitive data types in Java: byte, short, int, long, float, double, char, and

boolean.

Q4: What do you mean by abstract data types in Java?A4: Abstract data types are based on primitive data types and have more functionality than

the primitive data types. For example, String is an abstract data type that can store

alphabets, digits, and other special characters like /,();:$#. You cannot perform

calculations on a variable of the String data type even if the data stored in it has digits.

Q5: List out the rules for naming variables in Java.

A5: A Java variable name:

Must not be a keyword in Java.

Must not begin with a digit.

Must not contain embedded spaces.

Can contain characters from various alphabets like Japanese, Greek, and Cyrillic.