Data Types, Variables, & Expressions Flashcards
What is a primitive data type in Java?
It specifies the size and type of variable values and has no additional methods.
What are the most commonly used numeric types in Java?
- int (for whole numbers)
- double (for floating-point numbers).
What are the integer types available in Java?
- Byte
- Short
- Int
- Long
What are the floating-point types available in Java?
- Float
- Double
How should you indicate a long value in Java?
You should end the value with an “L”.
How should you indicate a float value in Java?
End the value with an “f”.
How should you indicate a double value in Java?
End the value with a “d”.
How can a floating-point number be expressed in scientific notation in Java?
Use an “e” to indicate the power of 10.
What values can the boolean data type in Java take?
The boolean data type can only take the values true or false.
What are boolean values mostly used for in Java?
Boolean values are mostly used for conditional testing.
What is the purpose of the char data type in Java?
The char data type is used to store a single character.
How should a character be enclosed in Java?
The character must be surrounded by single quotes, like ‘A’ or ‘c’.
What is the String data type used for in Java?
The String data type is used to store a sequence of characters (text).
How should String values be enclosed in Java?
String values must be surrounded by double quotes.
Why is String considered a non-primitive data type in Java?
Because String refers to an object.
What are non-primitive data types also known as, and why?
- ‘references’ because they refer to objects.
Can you name some examples of non-primitive data types in Java?
Examples include String, Arrays, Classes, and Interfaces.
How are primitive data types and non-primitive data types defined in Java?
Primitive types are predefined in Java, while non-primitive types are created by the programmer (except for String).
What is a key functional difference between primitive and non-primitive data types in Java?
Non-primitive types can call methods to perform operations, whereas primitive types cannot.
What is a key difference between primitive and non-primitive data types regarding their values?
A primitive type always has a value, while non-primitive types can be null.
How do the naming conventions differ between primitive and non-primitive data types in Java?
Primitive types start with a lowercase letter, while non-primitive types start with an uppercase letter.
What is the purpose of variables in Java?
Variables are containers for storing data values.
How can you ensure a variable’s value cannot be changed in Java?
Use the final keyword to declare the variable as “final” or “constant,” making it unchangeable and read-only.
What is type casting in Java?
It is when you assign a value of one primitive data type to another type.
What are the two types of type casting in Java?
- Widening Casting (automatically)
- Narrowing Casting (manually)
What is widening type casting in Java?
It is converting a smaller type to a larger type size.
What is narrowing type casting in Java?
It is converting a larger type to a smaller size type.
How can you combine text and a variable in Java?
Use the + character to concatenate text and a variable.
What are identifiers in Java?
Identifiers are unique names used to identify Java variables.
What is recommended when choosing identifiers for Java variables?
It is recommended to use descriptive names to create understandable and maintainable code.
