Using C/C++ it is possible to do the following:
int arr[100];
int ar[10][10];
memcpy(ar, arr, sizeof(int)*100);
Because the C/C++ standard guarantees that arrays are contiguous, the above will copy 1D array to 2D array.
Is this possible in Java ?
This is not possible in Java because a multidimensional array in Java is actually an array of arrays. The elements are not stored in a contiguous block of memory. You will need to copy the elements row by row.
For example, here's one of several possible techniques:
int arr[100] = . . .;
int ar[10][10] = new int[10][10];
int offset = 0;
for (int[] row : ar) {
System.arraycopy(arr, offset, row, 0, row.length);
offset += row.length;
}
From the Java Language Specification, §15.10.1, here are the steps that happen when evaluating the array creation expression new int[10][10] (note in particular the last point):
First, the dimension expressions are evaluated, left-to-right. If any of the expression evaluations completes abruptly, the expressions to the right of it are not evaluated.
Next, the values of the dimension expressions are checked. If the value of any DimExpr expression is less than zero, then a NegativeArraySizeException is thrown.
Next, space is allocated for the new array. If there is insufficient space to allocate the array, evaluation of the array creation expression completes abruptly by throwing an OutOfMemoryError.
Then, if a single DimExpr appears, a one-dimensional array is created of the specified length, and each component of the array is initialized to its default value (§4.12.5).
Otherwise, if n DimExpr expressions appear, then array creation effectively executes a set of nested loops of depth n-1 to create the implied arrays of arrays.
System.arraycopy, you can usejava.util.Arrays.copyOfRange(...). This doesn't create multi-dimensional arrays, but it can be used within the loop.java.lang.reflect.Arraycreates Dimensional Arrays. Then somehow index each dimension.