Why use finally block

why use finnaly block when we can close the resources after the try cath method has executed

The real reason is that you don't usually catch all exceptions (and you shouldn't). The code shown doesn't catch Errors for example, yet you would always want the resources allocated in the method to be released regardless of any exceptions that are thrown, not just the ones you catch yourself.

Similar Messages

Prb in using finally block......please help.

hi currently i am facing this problem when i tried using finally block. after recompile, it gave me a warning message or should i said is an error message. My error statement is as below,
C:\EKP\web\WEB-INF\classes\com\tms\report\model\ReportModule.java:393: warning: finally clause cannot complete normally
^
Note: C:\EKP\web\WEB-INF\classes\com\tms\report\model\ReportModule.java uses or overrides a deprecated API.
Note: Recompile with -deprecation for details.
1 warning
my code is as below,
try
service.deleteJobTask( task );
service.scheduleJob( task, schedule );
success = true;
catch( SchedulingException e )
Log.getLog( getClass() ).error( e.getMessage(), e );
finally
return success;
Please help me. Thank you very much
Regards.

Ditch the return statement in your finally clause and move it to the end of the try block in stead. The whole idea behind finally is that it is always executed even after you return from the method, you don't add a return statement to your finally.
In your case you don't need a finally clause, you only add calls to it that MUST be executed, such as freeing up resources.

Why try-finally block?

Why does java allow try with out catch? I can understand that try-finally can be used having the contained method to call throws {exception}. But why is a Try-finally clause allowed when contained method doesnt declare throws exception?

GermanShepherd wrote:
BalusC wrote:
What would be the benefit of that? If there is no try block, then there is nothing to catch and so there is also nothing to be done in the finally block.I understand that finally block in bytecodes is handled as a JSR call. Then why do we need try block at all. To put a boundary on which code is eligible for finally cleanup
a(); // if this throws exception, we'll leave the method immediately, no finally. Don't want to go to finally, since s doesn't exist yet
s = somethingThatNeedsCleanup();
try {
// do stuff with s
finally {
// clean up s
}

How to properly use finally block

I am writing a try-catch-finally block and I don't think it is written properly. I am using a BufferedReader and BufferedWriter like this:
BufferedReader myInput = null;
BufferedWriter myOutput = null;
try
    myInput = new BufferedReader(new FileReader(inputFile));
    myOutput = new BufferedWriter(new FileWriter(outputFile));
    // do stuff here
catch (IOException e)
    e.printStackTrace();
finally
    myInput.close();
    myOutput.close();
}Now the whole point of the finally block is that it gets executed no matter what, so I want to make sure that the input and output file get closed even if there is an exception thrown. However, when I try to compile this code it doesn't work because it complains that there are unhandled exceptions in the finally block.
What am I doing wrong here? If I have to put yet another try block inside of the finally block...doesn't that defeat the whole purpose of the finally block?

gamblor01 wrote:
I am writing a try-catch-finally block and I don't think it is written properly. I am using a BufferedReader and BufferedWriter like this:
BufferedReader myInput = null;
BufferedWriter myOutput = null;
try
myInput = new BufferedReader(new FileReader(inputFile));
myOutput = new BufferedWriter(new FileWriter(outputFile));
// do stuff here
catch (IOException e)
e.printStackTrace();
finally
myInput.close();
myOutput.close();
}Now the whole point of the finally block is that it gets executed no matter what, so I want to make sure that the input and output file get closed even if there is an exception thrown. However, when I try to compile this code it doesn't work because it complains that there are unhandled exceptions in the finally block.
What am I doing wrong here? If I have to put yet another try block inside of the finally block...doesn't that defeat the whole purpose of the finally block?You should also check myInput and myOutput references to make sure they are not null. If your first exception occurs during instantiation of your FileReader, for example, then myInput and myInput will both be null, causing a NullPointerException when you attempt to close them. Better to do something like:
finally
if ( myInput != null )
    myInput.close();
if ( myOutput != null )
    myOutput .close();
}� {�

Has anyone burned 1080p blu-ray discs using Final Cut Pro alone?

I am in the market for a new computer. Currently I am a PC user who has burned Blu-Ray discs using Pinnacle. I am dissatisfied with that software because it hangs and crashes at critical moments in the rendering and burn process. I am considering switching to Mac but will only do so if I can burn true Blu-Ray movies which are playable in an ordinary Blu-Ray player.
I have read some of the discussions on this board and it is not clear to me whether it is yet possible to burn 1080p Blu-Ray discs playable on any Blu-Ray player using Final Cut Pro alone. Can someone confirm for me whether they have done this? Some users have indicated they can only output 720p using Final Cut Pro (which is not very satisfying). Others have indicated it is necessary to use Adobe Encore. If you have to use Adobe Encore to burn, why use Final Cut Pro at all? Why not use Adobe Premier Pro for editing and Encore for burning?

David S. wrote:
And yes you can author single track 1080p blu ray discs with Compressor 3.5.
But that's not what the OP asked, "using FCP alone."
Why not use Adobe Premier Pro for editing and Encore for burning?
Well, why not just put CS4 on your PC, especially considering you already have the BD hardware?
There is no truth to the rumor that applications running on Macintosh are any more stable than the same apps a PC; all systems crash.
bogiesan

WHY CANT I USE FINAL CUT EXPRESS HD IN MY MACBOOK

WHY CANT I USE FINAL CUT EXPRESS HD IN MY MACBOOK?

hey there DavoMrMac,
according to Apple's 'site:
System Requirements
Macintosh computer with 500MHz or faster PowerPC G4 or G5 (550MHz for PowerBook G4) or Intel Core Duo
512MB RAM
Display with 1024-by-768 (or higher) resolution
An AGP or PCI Express graphics card compatible with Quartz Extreme or an Intel GMA integrated graphics processor in MacBook or Mac Mini
Mac OS X 10.4.6 or later
QuickTime 7.0.4 or later
HDV features require 1GHz or faster processor and 1GB of RAM (2GB recommended)
500MB disk space required for applications; additional 16GB of additional storage space for Soundtrack and LiveType content (can be installed on separate disks)
DVD drive for software installation
i've been running FCE HD 3.5 on my MacBook since i got it in November '06. runs okay for the few short SD projects(15:00) or less i've put together.

I am using final cut express. It seems that any clip over a certain length, say 5 min, does not fully transfer! All shorter clips are perfectly fine. Is there some reason why longer clips are not fully transferred? (a half blue circle shows up on the tran

I am using final cut express 4. It seems that any clip over a certain length, say 5 min, does not fully transfer! All shorter clips are perfectly fine. Is there some reason why longer clips are not fully transferred? (a half blue circle shows up on the transfer list, indicating that the clip was not fully transferred. When I check in the capture scratch folder, sure enough the whole clip is not there!
Is there some glitch in final cut express that only allows short clips to be transferred in full?

Thanks for the reply. I'll try to answer all the questions (I am a relative novice). Your help is appreciated.
By the way, the other reply I received suggested the following:
In Final Cut Express>System Settings>Scratch Discs make sure the Limit Capture/Export File Segement Size To: is not checked.
I did this and it was already unchecked. So this is not the answer...
The strange thing is, I have been logging and transferring with FCE for 2 yrs without any problems at all with shorter clips, but have come up against the problem with long clips (over 5 or so min) the whole time. I got around it by simply making sure I stopped recording after less than 5 min while shooting footage. OR if I accidentally got a long clip, I import into imovie and then import into FCE. Not very streamline and I worry about compressions altering quality!
I am now trying to import a 20 min and a 17 min clip and it only transfers around 3 minutes of each, I have re-tried several times and it happens repeatedly. The blue circle in the transfer list shows up as a half blue circle instead of full. Clip cuts off after 3 or so minutes.
ANSWERS
how you are ingesting the files
From external flash drive connected directly to mac using FCE.
the format of the source footage
digital via ext flash memory. Frame size :1929X1080 / 25fps
what camera shot the footage
SONY HXR NX5
how you are connecting to the computer
from flash memory directly via usb
what version of FCE you are using
4
what OS your computer is running
10.6.8
what model Mac
macbook Pro intel Core i7
what drive you are using for Capture Scratch
3TB external drive (plenty of room left)

Why do we use static block ????

my question is that why do we use static block for certain statements and declarations ?? what advantage do they hold???
Please help me........

Here is an example:
If you use a JDBC-driver, it's enough to write:
   String driverName = "package.MyDriver";
   Class.forName(driverName);In the class "MyDriver" there is a static block:
public class MyDriver implements java.sql.Driver {
   static {
      MyDriver driver = new MyDriver();
      java.sql.DriverManager.registerDriver(driver);
}

"Given final block not properly padded" when using wrong secretKey

Hello guys, I browsed the questions in this forum regarding my problem, but somehow couldn't find a solution to this.
I generated two SecretKey key1 and key2. Now I'm using the Cipher class to encrypt a message to key1. If I try to decrypt it with key1, everything works fine. But if I try key2 I get the "Given final block not properly padded"-message in my exception backtrace instead of just unreadable stuff, which I excepted (using the wrong key). This happens regardless of the symetric algorithm I use.
Can you help me?
Thanks,
Sebastian

Most symmetric algorithms work on data of a given block-size. If your data isn't a multiple of that size, it's padded. This removes a clue that a cryptanalyst can use to try and break your encryption. At decrypt time, the Cipher expects to see padding-related bits at the end of the stream, so it knows how many pad-bits were stuck on to begin with. When the end of the stream doesn't match the expected padding-protocol, you get the exception noted.
Now - if you decode with the wrong key, you get junk. The chances of that junk ending with a valid padding-indicator is...small. So you're more likely to see "BadPadding" than a valid (if incorrect) plaintext.
You could use "NoPadding" on both ends, and do your own manipulation of the bit-stream to make the Cipher happy. Then, you wouldn't get BadPadding exceptions. But you'd have to write some pretty fiddly code on each end.
Anybody else want to double-check me on this? I'm away from my books at the moment. Floersh? Euxx?
Good luck,
Grant

Why can't I use final cut pro 7 with Mavericks?

Why can't I use final cut pro 7 with Mavericks? Is any one else having problems? All my media is reputedly "offline" even though I can see all the files. Using the reconnect to media function doesn't do a thing. All of my previous projects are the same. Any ideas would be most welcome!

Because it is $299.99, and there is tax.
Cheers,
GB

If i use System.exit(0) in the catch block will finally block executed

If i use System.exit(0) in the try block or catch block will finally block will be executed?
try
System.exit(0);
catch(Exception e){
System.exit(0);
finally
System.out.println("finally!");
}

gavas_java_nov26_exception wrote:
If i use System.exit(0) in the try block or catch block will finally block will be executed?
try
System.exit(0);
catch(Exception e){
System.exit(0);
finally
System.out.println("finally!");
To tell you the truth, What does it matter? You shouldn't be doing that anyway, at least not in a well written program.
But, if you really want to find out, do as duffymo said, and try it. It'll only take a minute and save you the time (and embarressment) of asking here.

When I import a Quick Time movie into the timeline using Final Cut Express, why does it need rendering?

when I import a Quick Time movie into the timeline using Final Cut Express, why does it need rendering?

Because your clip properties do not match your sequence settings.
It will help a lot if you provide details ...
FCE Easy Setup
Sequence settings (vid rate, frame size, compressor)
Source of your clips (camcorder make/model, etc)
Clip properties (vid rate, frame size, compressor)

Who uses Final Touch SD in conjunction with FCP? Why? Why not?

Who uses Final Touch SD in conjunction with FCP? Why? Why not?
LM

It is my understanding that Final Touch is much faster than daVinci.
You are in error...
Depends on the operator and the machine. With a DaVinci you are going tape to tape and the colorist is coloring each shot. When they are done, then they press play and all their settings apply in real time as the tapes roll.
With Final Touch, you have to render your final product after you do all the coloring. Typically the render will take longer than it takes a tape to play, depending on the machines processor power. But still, 4-5 hours for a 30-60 minute show...darn slow. If you had the same colorist on both, Final Touch would be slower.
BUT...the advantage is that you color BEFORE you go to tape. So doing your texted and textless outputs are darn easy.
Shane

PBE; final block not properly padded help!

Hi there,
I'm having problems decrypting passwords using password based encryption (PBE), throwing me a "final block not properly padded" exception.
The passwords are also encrypted uses PBE in a seperate class called the PasswordEncryption. The code necessary to generate the Cipher is in a seperate method which is passed a String to determined if it would be initialized in "encrypt" or "decrypt" mode.
The class where the passwords are decrypted, UserManager, is passed the encrypted passwords as a String. It calls the PasswordEncryption class gets getcipher() to get the Cipher, and then decrypts the password. The data is read from the database by another class which reads database info, and passed in as a string to the decrypting class. The decrypting class converts the string to a byte[].
Below I have the UserManager class and PasswordEncryption class:
public class UserManager
implements SecurityServerInterface, PETComponent {
public UserManager() {
private static String decryptPassword(String asPassword) throws
SecurityException {
PasswordEncryption passwordEncryption = new PasswordEncryption();
Cipher pbeCipher = passwordEncryption.getCipher("decrypt");
String clearText = new String();
byte[] encryptedPassword = asPassword.getBytes();
try {
//This is where decryption failed! Given final block not properly padded
byte[] cipherText = pbeCipher.doFinal(encryptedPassword);
System.out.println(cipherText);
System.out.println("test cipher text");
clearText = new String(cipherText);
System.out.println("original:" + asPassword);
System.out.println("decrypted:" + clearText);
catch (IllegalBlockSizeException e) {
System.out.println(e.getMessage());
String illegalBlock = e.getMessage();
throw new SecurityException(illegalBlock);
catch (BadPaddingException e) {
System.out.println(e.getMessage());
String badPadding = e.getMessage();
throw new SecurityException(badPadding);
catch(Exception e) {
System.out.println(e.getMessage());
String exception = e.getMessage();
throw new SecurityException(exception);
System.out.println(clearText);
return clearText;
public class PasswordEncryption {
public static void main(String[] args) throws PETDBException,
SecurityEncryptionException {
PasswordEncryption encryptor = new PasswordEncryption();
ArrayList mainList = encryptor.getAllPasswords();
mainList = encryptor.encryptAllPasswords(mainList);
encryptor.updateAllPasswords(mainList);
public PasswordEncryption() {
//Get passwords from the user table of the database, e.g, loginName and passwords
private ArrayList getAllPasswords() throws PETDBException {
ArrayList passwordList = new ArrayList();
DBConnection.setConnection("jdbc:mysql://localhost/Mysql/data/pet?user=root&password=");
DBConnection dbCon = DBConnection.createConnection();
Connection con = dbCon.getConnection();
System.out.println(con);
try {
String allPasswordQuery = " SELECT " + DBColumns.USPASSWD.trim() + " , " +
DBColumns.USLOGINNAME.trim() + " from " + DBColumns.USER;
Statement stmt = con.createStatement();
ResultSet rs;
rs = stmt.executeQuery(allPasswordQuery);
if (rs.isFirst()) {
throw new PETDBException("No password found in the database.");
while (rs.next()) {
UserDO loUserDO = new UserDO();
loUserDO.setPassword(rs.getString(DBColumns.USPASSWD));
loUserDO.setLoginName(rs.getString(DBColumns.USLOGINNAME));
passwordList.add(loUserDO);
catch (SQLException sql) {
String sqlError = sql.getMessage();
throw new PETDBException(sqlError);
return passwordList;
private ArrayList encryptAllPasswords(ArrayList aoPasswordList) throws
SecurityEncryptionException {
// Encrypt the password
Cipher pbeCipher = getCipher("encrypt");
Iterator passwordIterator = aoPasswordList.iterator();
UserDO loUserDO = new UserDO();
try {
while (passwordIterator.hasNext()) {
loUserDO = (UserDO) passwordIterator.next();
String lsPassword = loUserDO.getPassword();
byte[] clearTextPassword = lsPassword.getBytes();
byte[] cipherText = pbeCipher.doFinal(clearTextPassword);
String cipherString = new String(cipherText);
loUserDO.setPassword(cipherString);
System.out.println(cipherString);
catch (IllegalBlockSizeException e) {
throw new SecurityException("Can't encrypt password, illegal block size");
catch (BadPaddingException e) {
throw new SecurityException("Can't encrypt password, bad padding");
System.out.println(aoPasswordList);
return aoPasswordList;
public Cipher getCipher(String mode) {
PBEKeySpec pbeKeySpec;
PBEParameterSpec pbeParamSpec;
SecretKeyFactory keyFac;
// Salt
byte[] salt = {
(byte)0xc7, (byte)0x73, (byte)0x21, (byte)0x8c,
(byte)0x7e, (byte)0xc8, (byte)0xee, (byte)0x99
// Iteration count
int count = 20;
// Create PBE parameter set & a SecretKey
pbeParamSpec = new PBEParameterSpec(salt, count);
SecretKey pbeKey;
// Use our own encryption password.
// Collect the password as char array and convert
// it into a SecretKey object, using a PBE key
// factory.
char[] password = new String("cmuw-team5").toCharArray();
pbeKeySpec = new PBEKeySpec(password);
try {
keyFac = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
pbeKey = keyFac.generateSecret(pbeKeySpec);
catch (NoSuchAlgorithmException e) {
throw new SecurityException("Can't collect password as a char array");
catch (InvalidKeySpecException e) {
throw new SecurityException("Can't convert password into a SecretKey Object");
// Create PBE Cipher
Cipher pbeCipher;
try {
pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
catch(NoSuchAlgorithmException e) {
throw new SecurityException("Can't create a PBE Cipher, no such algorithm");
catch(NoSuchPaddingException e) {
throw new SecurityException("Can't create a PBE Cipher, no such padding");
// Initialize PBE Cipher with key and parameters
if (mode == "encrypt") {
try {
pbeCipher.init(Cipher.ENCRYPT_MODE, pbeKey, pbeParamSpec);
catch(InvalidKeyException e) {
throw new SecurityException("Can't initialize PBE Cipher with key");
catch(InvalidAlgorithmParameterException e) {
throw new SecurityException("Can't initialize PBE Cipher with parameters");
if (mode == "decrypt") {
try {
pbeCipher.init(Cipher.DECRYPT_MODE, pbeKey, pbeParamSpec);
catch(InvalidKeyException e) {
throw new SecurityException("Can't initialize PBE Cipher with key");
catch(InvalidAlgorithmParameterException e) {
throw new SecurityException("Can't initialize PBE Cipher with parameters");
return pbeCipher;
//Get encrypted passwords out of the ArrayList and update the database
private void updateAllPasswords(ArrayList aoUpdatePasswordList) throws
PETDBException {
DataService dataService = new DataService();
Iterator getEncryptPassword = aoUpdatePasswordList.iterator();
String lsUpdatePassword = new String();
String lsUserName = new String();
Statement stmt;
DBConnection dbCon = DBConnection.createConnection();
Connection con = dbCon.getConnection();
try {
stmt = con.createStatement();
System.out.println(stmt);
catch (SQLException sql) {
String sqlError = sql.getMessage();
System.out.println(sqlError);
throw new PETDBException(sqlError);
while (getEncryptPassword.hasNext()) {
UserDO loUser = (UserDO) getEncryptPassword.next();
lsUpdatePassword = loUser.getPassword();
lsUserName = loUser.getLoginName();
String allUpdatePassword = " UPDATE " + DBColumns.USER + " SET " +
DBColumns.USPASSWD + " = " + "'" + lsUpdatePassword + "'" + " WHERE "
+ DBColumns.USLOGINNAME + " = " + "'" + lsUserName + "'";
System.out.println(allUpdatePassword);
try {
int returnValue = stmt.executeUpdate(allUpdatePassword);
System.out.println(returnValue);
catch (SQLException sql) {
String sqlError = sql.getMessage();
throw new PETDBException(sqlError);
try {
con.commit();
con.close();
catch (SQLException sql) {
String sqlError = sql.getMessage();
throw new PETDBException(sqlError);

Thanks for the prompt response! I got this example
from the Sun Java cryptography extensions web page at:
http://java.sun.com/j2se/1.4.2/docs/guide/security/jce/
CERefGuide.html#PBEExThe code I'm pointing out did not come from there. Nowhere in Sun's examples do you see them creating Strings directly from ciphertext. (Which is good, because if you did, their examples wouldn't work). To give some more context on where the problem is:private ArrayList encryptAllPasswords(ArrayList aoPasswordList) throws SecurityEncryptionException {
// Encrypt the password
Cipher pbeCipher = getCipher("encrypt");
Iterator passwordIterator = aoPasswordList.iterator();
UserDO loUserDO = new UserDO();
try {
    while (passwordIterator.hasNext()) {
      loUserDO = (UserDO) passwordIterator.next();
      String lsPassword = loUserDO.getPassword();
      byte[] clearTextPassword = lsPassword.getBytes();
      byte[] cipherText = pbeCipher.doFinal(clearTextPassword);
      // DOING THE FOLLOWING TO CIPHERTEXT TURNS IT INTO GARBAGE!
      String cipherString = new String(cipherText);
      loUserDO.setPassword(cipherString);
      System.out.println(cipherString);
} catch (IllegalBlockSizeException e) {
    throw new SecurityException("Can't encrypt password, illegal block size");
} catch (BadPaddingException e) {
    throw new SecurityException("Can't encrypt password, bad padding");
System.out.println(aoPasswordList);
return aoPasswordList;
}(Note: Please use the [ code ] tags when you post code - it makes it MUCH easier to figure out what you're doing.)
Also, my decryption code in the UserManager class does
work for two out of 8 users....I can't really figure
out why it's working for Only 2 users, and not the
rests. It's possible that the ciphertext is successfully string-able in those two cases (although I doubt it). But I can absolutely guarantee to you that trying to treat ciphertext as a String will turn your ciphertext into grabage, and that will result in a BadPaddingException when you decrypt. You need to stop doing that.
If you need to treat ciphertext or keys as Strings, the right way to do it is to Base64-encode the byte[] into a String, and then Base64-decode when you want to decrypt.
Grant

Restart fixes BadPaddingException: Given final block not properly padded ??

(I have seen quite a few posts on this and other forums regarding BadPaddingExceptions, however all of them seem to be easily reproducible. This one is random and has been impossible for us to reproduce in a test environment.)
Anyone have any idea why we might encounter this problem during decryption (e.g cipher.doFinal(<base64 encoded byte[]>) ) , but restarting the JVM clears it up?
Once it starts happening, all decryption fails with "BadPaddingException: Given final block not properly padded"
and once we restart the JVM, all is well again.
We are currently running j2sdk1.4.2_04 and are using PBEWithMD5AndDES.
Any help is much appreciated,
-Marc

I have plenty of ideas for what is wrong but why should I enumerate them. It would be much quicker if you posted (using [code] tags) your encryption and decryption code.
Edited by: sabre150 on Nov 29, 2007 12:09 PM

Why use finally block

Similar Messages

Maybe you are looking for