The simple principle and application of exception handling mechanism in Java? __java

When a Java program violates Java semantic rules, the Java virtual machine will take on the error table

is shown as an exception. The violation of the semantic rules consists of 2 cases. One is the semantic check built into the JAVA class library.

For example, an array subscript is out of bounds, and a indexoutofboundsexception is raised when an object that accesses null

Cause nullpointerexception. Another scenario is that JAVA allows programmers to extend this semantic check

Look, programmers can create their own exceptions and freely choose when to throw an exception with the Throw keyword.

All exceptions are java.lang.Thowable subclasses.