I have a small piece of code that runs through some transactions for processing. Each transaction is marked with a transaction number, which is generated by an outside program and is not necessarily sequenced. When I catch an Exception in the processing code I am throwing it up to the main class and logging it for review later. I'd like to add the transaction number to this thrown Exception. Is it possible to do this while still maintaining the correct stack trace?
For Example:
public static void main(String[] args) {try{processMessage();}catch(Exception E){E.printStackTrace();}}private static void processMessage() throws Exception{String transNbr = "";try{transNbr = "2345";throw new Exception();}catch(Exception E){if(!transNbr.equals("")){//stack trace originates from here, not from actual exceptionthrow new Exception("transction: " + transNbr); }else{//stack trace gets passed correctly but no custom message availablethrow E;}}}Best Answer
Try:
throw new Exception("transction: " + transNbr, E); Exceptions are usually immutable: you can't change their message after they've been created. What you can do, though, is chain exceptions:
throw new TransactionProblemException(transNbr, originalException);The stack trace will look like
TransactionProblemException : transNbrat ...at ...caused by OriginalException ...at ...at ...There is an Exception constructor that takes also the cause argument: Exception(String message, Throwable t).
You can use it to propagate the stacktrace:
try{//...}catch(Exception E){if(!transNbr.equals("")){throw new Exception("transaction: " + transNbr, E); }//...}you can use super while extending Exception
if (pass.length() < minPassLength)throw new InvalidPassException("The password provided is too short");} catch (NullPointerException e) {throw new InvalidPassException("No password provided", e);}// A custom business exceptionclass InvalidPassException extends Exception {InvalidPassException() {}InvalidPassException(String message) {super(message);}InvalidPassException(String message, Throwable cause) {super(message, cause);}}
}
source
You can write a Exception class extend from Exception and add attribute just like that:`public class PaymentException extends Exception {public Object data;
public PaymentException(Throwable cause) {super(cause);}public void setData(Object o) {data = o;}public Object getData() {return data;}}`
You can use your exception message by:-
public class MyNullPointException extends NullPointerException {private ExceptionCodes exceptionCodesCode;public MyNullPointException(ExceptionCodes code) {this.exceptionCodesCode=code;}@Overridepublic String getMessage() {return exceptionCodesCode.getCode();}public class enum ExceptionCodes {COULD_NOT_SAVE_RECORD ("cityId:001(could.not.save.record)"),NULL_POINT_EXCEPTION_RECORD ("cityId:002(null.point.exception.record)"),COULD_NOT_DELETE_RECORD ("cityId:003(could.not.delete.record)");private String code;private ExceptionCodes(String code) {this.code = code;}public String getCode() {return code;}}Following code is a simple example that worked for me.Let me call the function main as parent function and divide as child function.
Basically i am throwing a new exception with my custom message (for the parent's call) if an exception occurs in child function by catching the Exception in the child first.
class Main {public static void main(String args[]) {try{long ans=divide(0);System.out.println("answer="+ans);}catch(Exception e){System.out.println("got exception:"+e.getMessage());}}public static long divide(int num) throws Exception{long x=-1;try {x=5/num;}catch (Exception e){throw new Exception("Error occured in divide for number:"+num+"Error:"+e.getMessage());}return x;}} the last line return x will not run if error occurs somewhere in between.