Cause of the exception
This error can occur when we try to use negative sign with zero padding specifier %0Nd where N can be any integer.
package com.logicbig.example.illegalformatflagsexception;
public class IllegalFormatFlagsExceptionRightZeroPadding {
public static void main(String[] args) {
//right zero padding for integers not possible
System.out.printf("%0-5d", 21);
}
}
Output
java.util.IllegalFormatFlagsException: Flags = '-0'
at java.util.Formatter$FormatSpecifier.checkNumeric (Formatter.java:3181)
at java.util.Formatter$FormatSpecifier.checkInteger (Formatter.java:3136)
at java.util.Formatter$FormatSpecifier.<init> (Formatter.java:2874)
at java.util.Formatter.parse (Formatter.java:2713)
at java.util.Formatter.format (Formatter.java:2655)
at java.io.PrintStream.format (PrintStream.java:1209)
at java.io.PrintStream.printf (PrintStream.java:1105)
at com.logicbig.example.illegalformatflagsexception.IllegalFormatFlagsExceptionRightZeroPadding.main (IllegalFormatFlagsExceptionRightZeroPadding.java:13)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke (Method.java:564)
at org.codehaus.mojo.exec.ExecJavaMojo$1.run (ExecJavaMojo.java:282)
at java.lang.Thread.run (Thread.java:832)
Avoiding the exception
Avoid using negative sign for integer zero padding
package com.logicbig.example.illegalformatflagsexception;
public class IllegalFormatFlagsExceptionRightZeroPaddingFix {
public static void main(String[] args) {
//right zero padding for integers not possible
System.out.printf("%05d", 21);
}
}
Output
00021
