You, Mr., need to improve some things…
- Format your code. Even if it’s in the internet. And use // comments…
int size=32;
for(x=1; x<width*mapSize;x+=size) {
for(y=1;y<height*mapSize;y+=size) {
b.addBlock(new ObjTest(x,y); // this is what is being made
}
}
Or better: Format it right
Anyways, I like that you didn’t start like many other, who simply got here and asked how to do that without having done anything. Also, the code to be changed is already given, so guys, the answer is so simple?
Anyways 
The solution: Put less space between the y positions of your objects, because you’re not viewing from the top anymore, but from the side and also ‘indent’ objects at each 2nd row:
// I changed the code from
for(int x = 0; x < mapSize; x++) {
for(int y = 0; y < mapSize; y++) {
int xoffset = 0;
if (y % 2 == 0) // every second row
xoffset = width / 2; // Indent the row
b.addBlock(new ObjTest(xoffset + x * width, y * (height / 2)); // the magic happens here
// The two for-loops don't iterate through the
// world pixel-based anymore, but _block_ based.
// So I'm iterating the column and rows.
}
}
The equation got more complicated, but that’s the nature of isometric stuff.
More information:`
Hope that helps 