how to write an error java code example

Example: What is an error in Java

Error is the subclass of Throwable class in java. When errors are caused 
by our program we call that as Exception, but sometimes exceptions are 
caused due to some environment issues such as running out of memory. 
In such cases we can’t handle the exceptions. 
Exceptions which cannot be recovered are called as errors in java.
Ex : Out of memory issues