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Java Primitive Data Types

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Java Primitive Data Types

We have eight primitive data types in Java that store most raw numerical data in programs. They are:

  1. byte
  2. short
  3. int
  4. long
  5. char
  6. boolean
  7. float and
  8. double
Data Types in Java

Let us see the bytes they occupy and the ranges they could store in memory.

1. byte

A byte is an 8-bit signed integer.

  • Occupies 1 byte.
  • The default value is 0.
  • It can store a min value of -2^7 or -128 and a maximum value of (2^7 - 1) or 127.
public class ByteType {
    public static void main(String[] args) {
        byte A = -1;
        byte B = 20;
        byte C = 3;

        byte add = (byte) (B + C);
        byte subtract = (byte) (B - C);

        System.out.println(add); // 23
        System.out.println(subtract); // 17
    }
}

The maximum and minimum values of byte can be found at:

byte high = Byte.MAX_VALUE;   // high == 127
byte low = Byte.MIN_VALUE;    // low == -128

2. short

A short is a 16-bit signed integer.

  • Occupies 2 bytes.
  • The default value is 0.
  • It can store a min value of -2^15 or -32768 and a maximum value of (2^15 - 1) or 32767.
public class ShortType {
    public static void main(String[] args) {
        short A = -48;
        short B = 987;
        short C = 17;

        short add = (short) (B + C);
        short subtract = (short) (B - C);

        System.out.println(add); // 1004
        System.out.println(subtract); // 970
    }
}

The maximum and minimum values of short can be found at:

short high = Short.MAX_VALUE; // high == 32767
short low = Short.MIN_VALUE;  // low = -32768

3. int

This is one of Java's most used data types, storing 4 bytes of data. According to Java API, the Integer class wraps a value of the primitive type int in an object.

An int is a 32-bit signed integer.

  • Occupies 4 bytes.
  • The default value is 0.
  • It can store a min value of -2^31 or -2B and a maximum value of (2^31 - 1) or 2B.
public class IntType {
    public static void main(String[] args) {
        int A = -48;
        int B = 987;
        int C = 17;

        int add = B + C;
        int subtract = B - C;

        System.out.println(add); // 1004
        System.out.println(subtract); // 970
    }
}

The maximum and minimum values of short can be found at:

int max = Integer.MAX_VALUE; // -2147483648
int min = Integer.MIN_VALUE; // 2147483647

4. long

By default, long is a signed integer (In Java 8, it can be either signed/unsigned).

Signed: It can store a minimum of 2^63 and a maximum of (2^63 - 1).

Unsigned: It can store a minimum value of 0 and a maximum value of (2^64 - 1).

  • Occupies 8 bytes.
  • The default value is 0L.

If you assign long A = 100, Java assumes it as a int type. Appending L makes it a long.

public class LongType {
  public static void main(String[] args) {
    long A = -42;
    long B = 284;
    long C = 73;
    long bigNumber = 549755813888L;

    long addedLongs = B + C; // 284 + 73 = 357
    long subtractedLongs = B - C; // 284 - 73 = 211

    System.out.println(addedLongs); // 357
    System.out.println(subtractedLongs); // 211
  }
}

The maximum and minimum values of long can be found at:

// Max and Min
long high = Long.MAX_VALUE; // high == 9223372036854775807L
long low = Long.MIN_VALUE;  // low == -9223372036854775808L
Note: Letter L appended at the end of the long literal is case insensitive, however it is good practice to use capital as it is easier to distinct from digit one.
2L == 2l // true

5. char

A char can store a single 16-bit Unicode character. A character literal is enclosed in single quotes.

  • Occupies 2 bytes.
  • The default value is 0.
  • It can store a minimum value of \u0000 ( 0 in the decimal representation, also called the null character) and the maximum of \uffff or (2^16 - 1).
  • The char values are A, B, a, d, etc.
public class CharType {
  public static void main(String[] args) {
    char myChar = 'u'; // 'u'
    char myChar2 = '5'; // '5'
    char myChar3 = 65; // 'A'
  }
}

6. boolean

A boolean can store one of two values, either true or false.

  • Occupies 1 bytes.
  • The default value is false.
  • There is no min or max for boolean data type.
public class BooleanType {
  public static void main(String[] args) {
    boolean a = true; // true
    boolean b = false; // false
    
    boolean notA = !a; // false
    boolean notB = !b; // true
    
    boolean aAndB = a && b; // false
    boolean aOrB = a || b; // true
    
    boolean aXorB =a ^ b; // true
  }
}

7. float

A float is a single-precision 32-bit floating point number.

  • Occupies 4 bytes.
  • The default value is `0.0F`.
  • It can store a min value of -2^149 and a maximum value of 2^127.

By default, decimals are interpreted as doubles. To create a float, append an f to the decimal literal.

A float is precise to roughly an error of 1 in 10 million.

Float.POSITIVE_INFINITY
Float.NEGATIVE_INFINITY
Float.NaN

NaN stands for the results of an operation that cannot be determined. Such as dividing two infinite values.

public class FloatType {
  public static void main(String[] args) {
    float f1 = 0f;
    float f2 = -0f;
    System.out.println(f1 == f2); // true
    System.out.println(1f / f1); // Infinity
    System.out.println(1f / f2); // -Infinity
    System.out.println(Float.POSITIVE_INFINITY / Float.POSITIVE_INFINITY); // NaN
  }
}

0f and -0f are different but == yields true.

public class FloatType {
  public static void main(String[] args) {
    // addition
    float add = 37.2f + -2.6f; // result: 34.6
    System.out.println(add);

    // subtraction
    float subtract = 45.1f - 10.3f; // result: 34.8
    System.out.println(subtract);

    // multiplication
    float multiply = 26.3f * 1.7f; // result: 44.71
    System.out.println(multiply);

    // division
    float division = 37.1f / 4.8f; // result: 7.729166
    System.out.println(division);

    // modulus
    float modulus = 37.1f % 4.8f; // result: 3.4999971
    System.out.println(modulus);


  }
}

8. double

A double is a double-precision 64-bit floating point number.

  • Occupies 8 bytes.
  • The default value is `0.0D`.
  • It can store a min value of -2^1074 and a maximum value of 2^1023.
public class DoubleType {
  public static void main(String[] args) {
    double d1 = 0d;
    double d2 = -0d;
    System.out.println(d1 == d2); // true  
    System.out.println(1d / d1); // Infinity  
    System.out.println(1d / d2); // -Infinity 
    System.out.println(Double.POSITIVE_INFINITY / Double.POSITIVE_INFINITY); // NaN
  }
}
public class DoubleType {
  public static void main(String[] args) {
    double A = -7162.37;
    double B = 974.21;
    double C = 658.7;

    double addedDoubles = B + C; // 315.51 
    double subtractedDoubles = B - C; // 1632.91

    double scientificNotationDouble = 1.2e-3; // 0.0012
  }
}

Conclusion

In this article, we have seen how data is stored in Java programming language. In later articles, we will learn more about utilising these data types and manipulating application memory.