Java Challenge - Triangle Recursive

We have triangle made of blocks. The topmost row has 1 block, the next row down has 2 blocks, the next row has 3 blocks, and so on. Compute recursively (no loops or multiplication) the total number of blocks in such a triangle with the given number of rows.

triangle(0) → 0
triangle(1) → 1
triangle(2) → 3

Hisoka :

1 2 3 4

public int triangle(int rows) { if (rows == 0) return 0; return rows+triangle(rows-1); }

Test Result: