Help with while loop crashing game

Try checking if

Code (Java):

loc.getBlock().getRelative(BlockFace.DOWN).getType() != null) { }

and remove the semi colon after the if statement.

 

You really shouldn't be using a while loop in on the main thread . Just do all the pre calculations and place all the blocks. Like in a for loop. Keep decreasing the y axis and place a block until it hits the ground.

 

There's not really anything wrong in running a while loop in the main thread, as long as it's not infinite ofcourse, since that'll crash the server yes. As long as your while loop doesn't loop thousands of times, it shouldn't be any issue.

 

You can make something like this:

Code (Text):

int x = loc.getX();
int z = loc.getZ()
int y = loc.getY();// or something like this, writting on the phone
for(int i ; i< y - 1; i++){
   // test if the block bellow the y level of the lava - i is air, if it returns true, place a cobblestone, if not, break the loop then replace the lava with a cobblestone as well
}

 

I meant: use a for loop.

 

the main problem is in the while loop:

Code (Text):

while (loc.getBlock().getRelative(BlockFace.DOWN) != null); { //this is where everything goes wrong
                if (event.getBlock().equals(Material.AIR))
                    event.getBlock().setType(Material.COBBLESTONE);
                }    

the location is always in the same position that causing an infinite loop, you need to change the location to -1 y-axis when block below is solid until you get the block is non-solid.

but remember to check the y coordinate is equals or above 0.