Common Java Errors

1.NullPointerExceptin NULL pointer exception

A. References are used without initialization

B. The reference is empty and is still in use

2.IndexOutofBoundsException Subscript out of bounds

A. The array subscript is less than 0 or greater than the array. lenth

B. Using an array, when arrarylist the collection, note that JPanel will also be out of bounds, because when the layout is set to the grid column number is fixed, when adding too many controls will be out of bounds

3.NumberFormatException Numeric anomalies

A. Except for 0 operations

B. Errors in numeric operations, such as Integer.paseint ("abc"), and converting the string ABC to an integer.

4.IllegalArgumentException pass-through parameter error.

A. Correct parameters not required for incoming functions

　　

　　

Common Java Errors