Java Keywords and Identifiers
Q1. Why does a compilation error occur when using a Java keyword as a variable name ?
A compilation error occurs because keywords are reserved words in Java that have predefined meanings and are part of the language syntax.
For example, for is a keyword used to define loop statements. Java does not allow keywords to be used as variable names, method names, or class names.
Solution
Choose a valid identifier that is not a keyword, such as:
For example, for is a keyword used to define loop statements. Java does not allow keywords to be used as variable names, method names, or class names.
Solution
Choose a valid identifier that is not a keyword, such as:
- forCount
- loopCounter
Q2. Why cannot a Java class be declared using a keyword name ?
Java keywords cannot be used as class names because they are reserved for specific language constructs.
For example, int is a keyword used to declare integer variables. Declaring a class as:
will result in a compilation error.
Solution
Rename the class using a valid identifier, such as:
For example, int is a keyword used to declare integer variables. Declaring a class as:
public class int { }will result in a compilation error.
Solution
Rename the class using a valid identifier, such as:
- IntegerClass
- MyInt
Q3. Why are variable names not allowed to start with a digit in Java ?
Java identifier rules state that an identifier:
Valid alternatives include
- Cannot start with a digit
- Must begin with a letter, underscore (_), or dollar sign ($)
Valid alternatives include
- total123
- sum123
Q4. Does Java treat identifiers with different letter casing as the same ?
No, Java is a case-sensitive language.
This means identifiers such as Result and result are treated as two distinct variables, each storing its own value.
Case sensitivity helps Java differentiate between identifiers but also requires developers to follow consistent naming conventions to avoid confusion.
This means identifiers such as Result and result are treated as two distinct variables, each storing its own value.
Case sensitivity helps Java differentiate between identifiers but also requires developers to follow consistent naming conventions to avoid confusion.
Q5. Can the keyword record be used as a class name in Java ?
No, starting from Java 16, record is a contextual keyword used to define record classes.
Because it has a reserved meaning in the language, it cannot be used as a class name or identifier.
Using contextual keywords as identifiers leads to compilation errors, so developers should avoid naming conflicts with newer Java language features.
Because it has a reserved meaning in the language, it cannot be used as a class name or identifier.
Using contextual keywords as identifiers leads to compilation errors, so developers should avoid naming conflicts with newer Java language features.