Java Keywords and Identifiers
Interview Questions of keywords-and-identifiers
Scenario1: Variable Naming Error
Scenario:
You are writing a Java program and decide to name your integer variable for. When you try to compile, you get an error.
Question:
Why does this error occur, and how would you fix it ?
Answer:
The error occurs because for is a reserved keyword in Java, used for loops. Keywords cannot be used as variable names. To fix it, choose a different identifier, such as forCount or loopCounter.
Scenario:
You are writing a Java program and decide to name your integer variable for. When you try to compile, you get an error.
Question:
Why does this error occur, and how would you fix it ?
Answer:
The error occurs because for is a reserved keyword in Java, used for loops. Keywords cannot be used as variable names. To fix it, choose a different identifier, such as forCount or loopCounter.
Scenario 2: Class Declaration Confusion
Scenario:
A teammate tries to declare a new class as public class int { ... } but the code would not compile.
Question:
What is wrong with this class declaration ?
Answer:
int is a keyword in Java, used to declare integer variables. Keywords cannot be used as class names. The class should be renamed to something like IntegerClass or MyInt.
Scenario:
A teammate tries to declare a new class as public class int { ... } but the code would not compile.
Question:
What is wrong with this class declaration ?
Answer:
int is a keyword in Java, used to declare integer variables. Keywords cannot be used as class names. The class should be renamed to something like IntegerClass or MyInt.
Scenario 3: Identifier Rules
Scenario:
You want to create a variable named 123total to store a sum, but the IDE highlights it as invalid.
Question:
Why cannot you use 123total as a variable name, and what would be a valid alternative ?
Answer:
Identifiers cannot start with a digit. A valid alternative would be total123 or sum123.
Scenario:
You want to create a variable named 123total to store a sum, but the IDE highlights it as invalid.
Question:
Why cannot you use 123total as a variable name, and what would be a valid alternative ?
Answer:
Identifiers cannot start with a digit. A valid alternative would be total123 or sum123.
Scenario 4: Case Sensitivity
Scenario:
You have two variables in your code: Result and result. You assign different values to each.
Question:
Will Java treat these variables as the same or different ? Why ?
Answer:
Java is case-sensitive, so Result and result are treated as two distinct identifiers.
Scenario:
You have two variables in your code: Result and result. You assign different values to each.
Question:
Will Java treat these variables as the same or different ? Why ?
Answer:
Java is case-sensitive, so Result and result are treated as two distinct identifiers.
Scenario 5: Using Contextual Keywords
Scenario:
You want to use the word record as a class name in Java 16.
Question:
Will this work ? Why or why not ?
Answer:
No, starting from Java 16, record is a contextual keyword used to define record classes. It cannot be used as a class name.
Scenario:
You want to use the word record as a class name in Java 16.
Question:
Will this work ? Why or why not ?
Answer:
No, starting from Java 16, record is a contextual keyword used to define record classes. It cannot be used as a class name.