HTTP Status 500 - String index out of range: -10

Exception report\r

String index out of range: -10\r

The server encountered an internal error that prevented it from fulfilling this request.\r

java.lang.StringIndexOutOfBoundsException: String index out of range: -10

java.lang.String.substring(String.java:1911)

com.lib.DecryptUtil.fileDecrypt(DecryptUtil.java:22)

com.encrypt.Action.execute(Action.java:59)

sun.reflect.GeneratedMethodAccessor38.invoke(Unknown Source)

sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

java.lang.reflect.Method.invoke(Method.java:606)

com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:452)

com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:291)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:254)

com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:176)

com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)

com.opensymphony.xwork2.DefaultActionInvocat