External Interfaces/API

Creating a New Array Reference

Because Java arrays in MATLAB are references, assigning an array variable to another variable results in a second reference to the array.

Consider the following example where two separate array variables reference a common array. The original array, origArray, is created and initialized. The statement newArrayRef = origArray creates a copy of this array variable. Changes made to the array referred to by newArrayRef also show up in the original array.

• origArray = javaArray('java.lang.Double', 3, 4);
  for m = 1:3
     for n = 1:4
        origArray(m,n) = java.lang.Double((m * 10) + n);
     end
  end
  
  origArray
  origArray =
  java.lang.Double[][]:
      [11]    [12]    [13]    [14]
      [21]    [22]    [23]    [24]
      [31]    [32]    [33]    [34]
  
  %  ----- Make a copy of the array reference -----
  newArrayRef = origArray;
  newArrayRef(3,:) = java.lang.Double(0);
  
  origArray
  origArray =
  java.lang.Double[][]:
      [11]    [12]    [13]    [14]
      [21]    [22]    [23]    [24]
      [ 0]    [ 0]    [ 0]    [ 0]
  

Concatenating Java Arrays

Creating a Copy of a Java Array