[jboss-jira] [JBoss JIRA] Commented: (JASSIST-132) Replacing an expression with a try-catch statement

[ https://jira.jboss.org/browse/JASSIST-132?page=com.atlassian.jira.plugin.... ] Shigeru Chiba commented on JASSIST-132: --------------------------------------- Let me explain why a try-catch statement cannot substitute an expression. While computing an expression, intermediate results are saved on a stack. Then, if an exception is thrown, the JVM discards all the values on the stack. To come back from a catch clause, the broken stack must be restored but it is really difficult since the stack height (and the values there) is different depending on when the exception is thrown. A possible approach is this. If the code is: Utils.addStringError("s1", "s2") it should be transformed into: Utils.addStringErrorTrap("s1", "s2") : private void addStringErrorTrap(String s1, String s2) { printf("Arguments: %s, %s\n", "s1", "s2"); try { String s = Utils.addStringError("s1", "s2") printf("Result: %s\n", s); } catch (Throwable t) { printf("Error: %s\n", t.getMessage()); } } A tip is to make a new method addStringErrorTrap. An exception does not discard stack values used by other methods. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: https://jira.jboss.org/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira