The Java Developers Almanac 1.4


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Home > List of Packages > java.util  [50 examples] > Arrays  [5 examples]

e338. Comparing Arrays

    // null arrays are equal
    boolean[] bArr1 = null;
    boolean[] bArr2 = null;
    boolean b = Arrays.equals(bArr1, bArr2);                   // true
    
    // Compare two boolean arrays
    bArr1 = new boolean[]{true, false};
    bArr2 = new boolean[]{true, false};
    b = Arrays.equals(bArr1, null);                            // false
    b = Arrays.equals(bArr1, bArr2);                           // true
    
    // There are equals() methods for all eight primitive types
    b = Arrays.equals(new byte[]{0}, new byte[]{0});           // true
    b = Arrays.equals(new char[]{'a'}, new char[]{'a'});       // true
    b = Arrays.equals(new short[]{0}, new short[]{0});         // true
    b = Arrays.equals(new int[]{0}, new int[]{0});             // true
    b = Arrays.equals(new long[]{0L}, new long[]{0L});         // true
    b = Arrays.equals(new float[]{0F}, new float[]{0F});       // true
    b = Arrays.equals(new double[]{0D}, new double[]{0D});     // true
    
    // When comparing Object arrays, null elements are equal.
    // If the elements are not null, Object.equals() is used.
    b = Arrays.equals(new String[]{"a"}, new String[]{"a"});   // true
    b = Arrays.equals(new String[]{null}, new String[]{null}); // true
    b = Arrays.equals(new String[]{"a"}, new String[]{null});  // false

 Related Examples
e1072. Filling Elements in an Array
e339. Shuffling the Elements of a List or Array
e340. Converting a Collection to an Array
e341. Converting an Array to a Collection

See also: Bits    Collections    Dates    Hash Tables    Lists    Property Files    Sets    Sorted Collections    Time    Timers   


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