Help try catch

im experiment trying to make a calculator applet and have the usual:
plus
minus
multiply
divide
etc
which i have enclosed the action to these buttons in a try catch to ensure data is entered and it is correct. I have also 4 special buttons that i want to add but dont need any data to be entered so i have placed them outside the {} of the try catch but when i click on buttons it seems they are still being caught in the try catch
any help would be most appricated

Well,
Its very difficult to say why your unguarded code is behaving like the guarded section as if it is inside try block.
better post ur code along with your query, it will help analyze the problem better.
Kind Regards
Rahul Bajaj

Similar Messages

How to accept 2 strings in a class with try catch method..help!!

the program below will accept two strings and compare str1 and str2 if equal. this program uses functions. can any one help me with this?
import java.io.*;
public class StrCompare {
     private BufferedReader takyoin = null;
     //private BufferedReader intakyo = null;
     * @param args
     public StrCompare(){
          takyoin = new BufferedReader(new InputStreamReader(System.in));
          //intakyo = new BufferedReader(new InputStreamReader(System.in));
     public String UserInput(){
     public static void main(String[] args) {
          // TODO Auto-generated method stub
}

What are you talking about? There is no such thing as "try-catch-methods", and there are no functions but methods.
Strings by the way have their own means of comparision. Apart from that: do your own homework.

Please help with try/catch

Hello, I'm writing a program and I got surprised with the following. I've got the following try/catch block:
try {
String param = config.getConfigValue("db2.driver");
if (param == null)
// parameter not defined.
throw new Exception("Parameter 'db2.driver' missing!");
else
Class.forName(param);
catch (SQLException sqlEx) {
// do something
catch (Exception e) {
System.out.println("*** ERROR loading driver..."); (1)
finally {
releaseDB2Resources();
I know the program flow goes through the finally block, but it doesn't print the message (1). Why is that? I don't understand it. What am I doing wrong?
Thanks in advance.

A finally block always gets executed, so that's why the println always works there. The only reason why the println in the catch wouldn't work is if that exception wasn't thrown. If a config value is not there, it might be the null string "" instead of null. Try this:
if (param.equals(""))
throw new Exception("blah");
You could also try:
if (true)
throw new Exception("blah");
to make sure that the exception is caught where you think it should be.

Need HELP with finally() in nested try-catch

hi,
i am having trouble with deadlock and wondering if its due to an incorrect use of finally nested within multiple try catch blocks.
is the inner finally() required, will the outer one get executed, or will the two finally() statements get executed...??
the deadlock happens very infrequently to accurately test.
try {
     try {
     catch (InterruptedException e) {
          return;
catch {
finally {
     //will this be executed be executed by the inner throw statement
}or is an inner finally required
try {
     try {
     catch (InterruptedException e) {
          return;
     //this finally is NEW....is it needed!
     finally {
          //will this be executed. will both get executed
catch {
finally {
     //will this be executed also, or completely ignored if exception throw from inner try/catch
}

inner/outer, which one is executed first?
more info pls.I mean, really. How hard is it to find out for yourself?
public class TestFinally {
    public static void main(String[] args) {
        try {
            try {
                throw new RuntimeException("Whatever");
            } finally {
                System.out.println("Inner finally");
        } finally {
            System.out.println("Outer finally");
}I'll leave it to your imagination as to how to modify this class to confirm the answers to your original question.

Help regarding try catch!

In the following code, when the exception occurs at b, the control goes to the catch block! however, though the values for c, d are perfect, they are never reached!
Is there anyway to make the control return to where the exception was thrown & continue from there?
int a=0,b=0,c=0,d=0,
try {
          a = Integer.parseInt("11");
          b = Integer.parseInt("aa");
          c = Integer.parseInt("33");
          d = Integer.parseInt("44");
     } catch(Exception ex) {
          System.out.println("Except occured: " + ex);
     }

No.
If you want that other code to execute it would need a seperate try/catch block OR to go in the finally block. Whatever you feel.

Help, try and catch and variables

I have a private vector in one of my objects, i then add some items to it at the beginning of a method, the program then goes into a try/catch block where i add some more variables.
However, the variables i add in the try/catch block only seem to exist within that block.
In another method i refer to the vector again, but it only contains the elements i added before the try/catch block.
Any suggestions?

headers = new Vector();
headers.add("String 1");
headers.add("String 2");
connect("database");
System.out.println("Connected");
try
String mySQL = "SELECT * FROM " + table;
Statement st = c.createStatement();
System.out.println("Statement Created");
st.executeQuery(mySQL);
catch (Exception e)
try
StringTokenizer tk = new StringTokenizer(layoutString, "|");
while (tk.hasMoreTokens())
String tmpStr = tk.nextToken();
if (tmpStr.equalsIgnoreCase("ScalePanel"))
String tmp = tk.nextToken();
headers.add(tmp);
headers.add("number");
else if (tmpStr.equalsIgnoreCase("OptionPanel"))
String tmp = tk.nextToken();
headers.add(tmp);
headers.add("varchar(20)");
else if (tmpStr.equalsIgnoreCase("InputPanel"))
String tmp = tk.nextToken();
headers.add(tmp);
headers.add("varchar(20)");
System.out.println("Table Doesn't Exist, creating...");
String mySQL = "create table " + table + " (";
for (int i = 0 ; i < headers.size() ; i++)
if (i == 0)
mySQL += headers.get(i) + " " + headers.get(++i);
else
mySQL += "," + headers.get(i) + " " + headers.get(++i);
mySQL += ");";
Statement st = c.createStatement();
st.execute(mySQL);
catch (Exception ex)
System.out.println("Error while creating table");
System.out.println(ex.getMessage());
disconnect();
I then refer to headers in another method, but it only contains the items before the try/catch.

Help with reducing try catch blocks

Hi,
I have an object of a class having about 100 get methods. I have about 300 such objects. I want to get all the parameters from all the 100 get methods for all the objects, and for each failed get methods, an exception occurs,
Now I can loop from - to no of objects but inside I have to declare 100 try catch methods for each get methods.
for(i=0;i< 300;i++) {
try {
   a.getname;
catch { --- }
try{
a[i].getno ;
catch { -- }
100 such a[i].getXYZ methods
any alternative. wanted to avoid all the try catch statements
Please suggest
thanks

tarkesh wrote:
Its actually a serialized object, which I am trying to extract parameters from. So I actually need to know exactly which get method is failing for which object, as the objects can be in error when they get transported over the network.If it was me I would generate the code so the actual mechanism becomes moot.
But you can use something like the following (generated or not.)
       String attrName="<Unknown>"
       try
             attrName = "attr1";
             attr1=instance.attr1;
             attrName = "attr2";
             attr2 = instance.attr2;
       catch(Exception e)
             // attrName has correct name here.
       }

OutOfMemory Exceptions on Servlets, Try-Catch unable to help

Hi, I'm playing with Java servlets right now and I seem to be getting some OutOfMemory errors. The weird thing is that even though I had identify the souce of error and tried to enclose it with a try-catch, the exception still occurs. Why is that so?

OutOfMemoryError is actually a java.lang.Error, not a RuntimeException. So if you use a try/catch like this
try {
// stuff
} catch (Exception e) {..}Errors will fall through, since Error is not a subtype of Exception. (Check the API.)
You can catch it by catching Error or Throwable, like this:
try {
// stuff
} catch (Error e) { // this is rarely a good idea
}But you normally wouldn't want to do this. When there's no memory left, there's not a whole lot you can do about it, and most of the code you might want to put inside the catch block will merely throw another OutOfMemoryError.
As voronetskyy said, you're either creating too many (or too large) objects (typically in an endless loop), or you have specified too little memory for your application.

Can't find class because of try catch block ?!

Hello,
I'm using the JNI to use a java library from my c++ code.
JNI can't find the "Comverse10" class below, but when i put the try catch block in createMessage in comment, FindClass succeeds ?!
Unfortunatly i need the code inside the try block ;-)
I tried a few things, but none of them worked:
- let createMessage throw the exception (public void createMessage throws ElementAlreadyExistsException ), so there isn't a try catch block in createMessage => result: the same
- make a "wrapper" class Comverse that has a Comverse10 object as attribute and just calls the corresponding Comverse10.function. Result: Comvers could be found, but not constructed (NewObject failed).
Can someone tell me what is going on ?!
Thank you,
Pieter.
//Comverse10 class
public class Comverse10 {
MultimediaMessage message;
/** Creates a new instance of Comverse10 */
public Comverse10() {
public void createMessage() {
TextMediaElement text1 = new TextMediaElement("Pieter");
text1.setColor(Color.blue);
SimpleSlide slide1 = new SimpleSlide();
//if i put this try catch block in comment, it works ?!
try{
slide1.add(text1);
catch(com.comverse.mms.mmspade.api.ElementAlreadyExistsException e){}
MessageContent content = new MessageContent();
content.addSlide(slide1);
this.message = new MultimediaMessage();
message.setContent(content);
message.setSubject("Mijn subjectje");
for those of you who are intersted: here's my C++ code:
//creation of JVM
HRESULT Java::CreateJavaVMdll()
     HRESULT HRv = S_OK;
char classpath[1024];
     jint res;
     if(blog)     this->oDebugLog->Printf("CreateJavaVMdll()");
     strcpy(classpath,"-Djava.class.path="); /*This tells jvm that it is getting the class path*/
     strcat(classpath,getenv("PATH"));
     strcat(classpath,";D:\\Projects\\RingRing\\MMSComposer;C:\\Progra~1\\j2sdk1~1.1_0\\lib");     //;C:\\Comverse\\MMS_SDK\\SDK\\lib\\mail.jar;C:\\Comverse\\MMS_SDK\\SDK\\lib\\activation.jar;C:\\Comverse\\MMS_SDK\\SDK\\lib\\mmspade.jar
     //------Set Options for virtual machine
     options[0].optionString = "-Djava.compiler=NONE"; //JIT compiler
     options[1].optionString = classpath;                                        //CLASSPATH
     //------Set argument structure components
     vm_args.options = options;
     vm_args.nOptions = 2;
     vm_args.ignoreUnrecognized = JNI_TRUE;
     vm_args.version = JNI_VERSION_1_4;
     /* Win32 version */
     HINSTANCE hVM = LoadLibrary("C:\\Program Files\\j2sdk1.4.1_01\\jre\\bin\\client\\jvm.dll");
     if (hVM == NULL){
          if(blog) oDebugLog->Printf("Can't load jvm.dll");
          return E_FAIL;
     if(blog) oDebugLog->Printf("jvm.dll loaded\n");
     LPFNDLLFUNC1 func = (LPFNDLLFUNC1)GetProcAddress(hVM, "JNI_CreateJavaVM");
     if(!func){
          if(blog)     oDebugLog->Printf("Can't get ProcAddress of JNI_CreateJavaVM");
          FreeLibrary(hVM);     hVM = NULL;
          return E_FAIL;
     if(blog)     oDebugLog->Printf("ProcAddress found");
     res = func(&jvm,(void**)&env,&vm_args);
     if (res < 0) {
if(blog)     oDebugLog->Printf("Can't create JVM with JNI_CreateJavaVM %d\n",res);
return E_FAIL;
     if(blog)     oDebugLog->Printf("JVM created");
     return HRv;
//finding Comverse10 class:
HRESULT CALLAS MMSComposer::InitializeJNI(void)
     HRESULT HRv=E_FAIL;
     DWORD T=0;
     try
          if(blog)     oDebugLog->Printf("\nInitializeJNI()");
          bJVM = FALSE;
          jni = new Java(oDebugLog);
          if(jni->CreateJavaVMdll()!=S_OK){
               if(blog)     oDebugLog->Printf("CreateJavaVMdll() failed");
               return HRv;
          jclass jcls = jni->env->FindClass("Comverse10");
          if (jcls == 0) {
if(blog)     oDebugLog->Printf("Can't find Comverse10 class");
               jclass jcls2 = jni->env->FindClass("test");
               if (jcls2 == 0) {
                    if(blog)     oDebugLog->Printf("Can't find test class");
                    return HRv;
               if(blog)     oDebugLog->Printf("test class found %08x",jcls2);
return HRv;
          if(blog)     oDebugLog->Printf("Comverse10 class found %08x",jcls);
          jmethodID mid = jni->env->GetMethodID(jcls , "<init>", "()V");
          if (mid == 0) {
               if(blog)     oDebugLog->Printf("Can't find Comverse10() constructor");
return HRv;
          if(blog)     oDebugLog->Printf("Comverse10() constructor found");
          jobject jobj = jni->env->NewObject(jcls,mid);
          if(jobj==0)
               if(blog)     oDebugLog->Printf("Can't construct a Comverse10 object");
return HRv;
          if(blog)     oDebugLog->Printf("Comverse10 object constucted");
          //Create Global reference, so java garbage collector won't delete it
          jni->jobj_comv = jni->env->NewGlobalRef(jobj);
          if(jni->jobj_comv==0)
               if(blog)     oDebugLog->Printf("Can't create global reference to Comverse10 object");
return HRv;
          if(blog)     oDebugLog->Printf("global reference to Comverse10 object %08x created",jni->jobj_comv);
          bJVM=TRUE;
          HRv=S_OK;
     }     catch( IDB * bgError ) { throw bgError->ErrorTrace("InitializeJNI::~InitializeJNI",HRv, 0, T); }
          catch(...) { throw IDB::NewErrorTrace("InitializeJNI::~InitializeJNI",HRv, 0, T ); }
          return HRv;

>
I would guess that the real problem is that that the
exception you are catching is not in the class path
that you are defining.Thanks jschell, that was indeed the case.
I don't have the docs, but I would guess that
FindClass() only returns null if an exception is
thrown. And you are not checking for the exception.
Which would tell you the problem.Ok, i'll remember that. But what with exceptions thrown in my java code, the documents say
// jthrowable ExceptionOccurred(JNIEnv *env);
// Determines if an exception is being thrown. The exception stays being thrown until either the native code calls ExceptionClear(), or the Java code handles the exception
so, what if the java code throws an exception and catches it, will i be able to see that in my c++ code with ExceptionOccurred ?
or
should the java method be declared to throw the exception (and not catch it inside the method)
Again, thank you for your help, it's greatly appreciated !

Can we have try/catch in a static block in a class?

hi All
i have a question about put a try/catch block in a static block in a class to catch exceptions that maybe thrown from using System.xxxx(). in my custom class, i have a static block to initialize some variables using System.xxx(). in case of any error/exception, i need to be able to catch it and let the caller know about it. i tried to put a try/catch block in the static block, and tried to rethrow the exception. but it is not allowed, how would i handle situation like this? thanks for your help and advise in advance.

You could just swallow the exception inside try/catch
block, and instead of throwing it out, just set a
static variable to allow checking from outside
whether the initialization succeeded, or check within
the constructor / methods of this class for
successful initialization, and throw the exception
then. You could even save that exception in a static
variable for later.Ouch, ouch, you're hurting my brain. This would allow someone to ignore a (presumably) fatal error. Throw a RuntimeException as indicated. You can wrap a checked exception in an unchecked one if need be.

Exception handling with try/catch in acrobat

Hi
I have a problem using a try/catch block in my acrobat document-script. Try to enter the following into the debugger-console:
try{nonexistentFunction();}catch(e){console.println('\nacrobat can't catch')}
and run it. The output will be:
nonexistentFunction is not defined
1:Console:Exec
acrobat can't catch
true
The whole point of a rty/catch block is for the application NOT to throw an exception, but instead execute the catch-part of the statement. However, acrobat does both: It throws an exception AND executes the catch-block.
Is there another way to suppress the exception, or to make the try/catch-block work as it's supposed to?

> Also Adobe provides for free the JS or compiled file for Acrobat Reader to support the JS console.
Where is that file located ? How to install it or where to place it ?
What is the method referred by try67 on his site where he sells a product ?
Is that the same as the compiled file you refer to ? or did he sell his solution to adobe ?
It is helpful if people can get an idea of the nature of choices available and make informed decisions, than a cloak and dagger approach.
For some jobs that we have, I have been very frustrated by a consultant who wont even give basic info for transparent billing despite all assurances for privacy, as a result we are forced to do the job ourselves.
Dying Vet

About the finally block of the try catch.

I know that finally block contains the code that will be executed in any condition of the try catch.
However, I think it is unneccessary, since the stack after the try catch stack will be executed any way.
Any one can help?
for example
try{
System.in.read();
catch(Exception e){}
finally
{ System.out.println("does this matter?");}and
try{
System.in.read();
catch(Exception e){}
System.out.println("does this matter?");

However, I think it is unneccessary, since the stackafter the try catch
stack will be executed any way.That does assume that you catch and handle the error
appropriately.
Of course this is valid as well, and demonstrates
when you would WANT a finally clause.
Connection con = null;
Statement stmt = null;
try{
con = Database.getConnection();
stmt = con.createStatement("Select * from dual");
// maybe something throws an exception here?
finally{
if (stmt != null){
stmt.close();
if (con != null){
con.close();
The finally block here might throw a null pointer exception itself use
null!=stmt null!=stmt

Return statement and Try Catch problem

Hi!!
I've got the next code:
public ResultSet DBSelectTeam(String query) {
try {
Statement s = con.createStatement();
ResultSet rs = s.executeQuery(query);
return rs;
} catch (Exception err) {
JOptionPane.showMessageDialog(null, "ERROR: " + err);
But I need a return statement in the catch-block, but I don't know what's the best option.
Help...
Many thanks.

The error message is: "missing return statement", Yes, I know.
You have to either return from the catch statement, or throw from the catch statement, or return or throw after the catch statement.
The only ways your method is allowed to complete is by returning a value or throwing an exception. As it stands, if an exception is thrown, you catch it, but then you don't throw anything and you don't return a value.
So, like I said: What would you return from within or after catch? There's no good value to return. The only remotely reasonable choice would be null, but that sucks because now the caller has to explicitly check for it.
So we conclude that catch shouldn't return anything. So catch must throw something. But what? You could wrap the SQLE in your own exception, but since the caller is dealing with JDBC constructs anyway (he has to handle the RS and close it and the Statement), there's no point in abstracting JDBC away. Plus he has to deal with SQLE anyway in his use of the RS and Statement. So you might as well just throw SQLE.
So since you're going to just throw SQLE anyway, just get rid of the try/catch altogether and declare your method throws SQLException

Yet another Try Catch question. Iterating through a ForEach loop

Confused on error handling in a Powershell ForEach loop. I’m looping through a list of registry keys, attempting
to open each one. If it succeeds, I do a bunch of stuff. If it fails, I want to skip to the next iteration.
If I was doing It in VBScript I’d do this:
For Each Thing In colThings
Open Thing
If Err.Number <> 0 Then
“oops”
Else
Do stuff
Do stuff
Do stuff
End If
Next
This is what I came up with in PowerShell. It seems to work, but just doesn’t seem powershell-ish. There must be a better way to use the catch output than just creating a $return variable and assigning it success or fail?
ForEach ($subKeyName in $subKeyNames)
try{$subKey = $baseKey.OpenSubKey("$subKeyName")}
catch{$return = "error" }
If($return -eq "error" )
“Oops”
Else
Do stuff
Do stuff
Do Stuff

I totally get what you're saying about formatting. I don't' have any habits yet, since I've only been working in Powershell since... well, what time is it now?
Unfortunately, It Has Been Decreed that we are no longer to use VBScript for any engineering solutions at work, so my 15 years experience in it now needs to be transitioned over asap. I don't have the luxury of crawling before I run. I'm trying not to be
frustrated, but it's like an English major waking up one day and being told "You must now speak French exclusively. Here's a book."
The Do Stuff example of my ForEach loop is about 50 lines of code involving matching values in subkeys of this registry key with another and collecting output. I tried wrapping the whole thing in a try section based on some examples, but it seemed odd, that's
why I'm asking. I'm used to tightly focused error handling at the point where an error may occur.
In this example I'm only interested in whether or not I can open the subkey (it exists, but I may not have permission). If I can't, there's no point in continuing with this iteration of the loop, I want to skip to the next one. So why include all the "Do
Stuff" in the the try section? From a readability viewpoint, it doesn't seem helpful.
Also, there may be more error handling deeper in the code. If I then put that in a try/catch, and then something else inside that, now I have nested try/catches mixed in with nested if/elses, all wrapped in a For loop.
Again, I can see how it works logically, but for readability not so much, and having all these braces 50 lines apart to match up is giving me eye strain :).
It sounds like David is agreeing with jrv, that putting the entire ForEach loop code into a try/catch is the conventional way to do it. I guess it makes as much sense as putting it all in an If-else-Endif, and I just need to adjust my paradigm.
But if not, my specific question was more along the lines of, is there a built in way to tell that the catch section has been executed, rather than me using it to populate an arbitrary variable and then read it? In VBScript, you execute something, and the
next line, you check the Err.number. I wasn't sure if you could do that with a try/catch.

Try catch implementation in dynamic query

I am fetching values by dynamic selection (select a,b,..from (var)...) .
Eveytime if I am selecting garbage value of var it will throw dump . Can u tell me how we implement try catch method / exception handling method so that I can avoid dump in dynamic query
Appropriate answer will rewarded with points that is for sure .

Here is the usage of th try statements ...
PARAMETERS number TYPE i.
DATA: result TYPE p LENGTH 8 DECIMALS 2,
      oref   TYPE REF TO cx_root,
      text   TYPE string.
TRY.
    IF ABS( number ) > 100.
      RAISE EXCEPTION TYPE cx_demo_abs_too_large.
    ENDIF.
    PERFORM calculation USING    number
                      CHANGING result
                               text.
CATCH cx_sy_arithmetic_error INTO oref.
    text = oref->get_text( ).
CATCH cx_root INTO oref.
    text = oref->get_text( ).
ENDTRY.
IF NOT text IS INITIAL.
WRITE / text.
ENDIF.
WRITE: / 'Final result:', result.
FORM calculation USING    p_number LIKE number
                 CHANGING p_result LIKE result
                          p_text   LIKE text
                          RAISING cx_sy_arithmetic_error.
DATA l_oref TYPE REF TO cx_root.
TRY.
      p_result = 1 / p_number.
      WRITE: / 'Result of division:', p_result.
      p_result = SQRT( p_number ).
      WRITE: / 'Result of square root:', p_result.
    CATCH cx_sy_zerodivide INTO l_oref.
      p_text = l_oref->get_text( ).
    CLEANUP.
      CLEAR p_result.
ENDTRY.
ENDFORM.
<b>please see this link for detailed explaination of the TRY & ENDTRY ...</b>
<a href="http://">http://help.sap.com/saphelp_nw04/helpdata/en/a9/b8eef8fe9411d4b2ee0050dadfb92b/content.htm</a>
reward points if it is usefull......
Girish

Help try catch

Similar Messages

Maybe you are looking for