If I put the highlighted text in try/catch block it is throwing NullPointerException , if I am using command line arguments then also it is showing the same exception.
public static void main(String []args)
args = null;
args[0] = "test";
System.out.println(args[0]);
I came across a code where the exceptions can be thrown from catch and finally block too. I never gave a thought on what scenarios that can be required. Some practical examples when/where it can be required to throw the exception from catch and finally blocks.
View Replies View Relatedimport java.io.*;
class Base
{
void get()throws Exception{}
}
class Excep extends Base
[code]....
In above even though exception is handled in catch block still it shows an error?
java 7 feature (Multicatch and final rethrow ).. how to print user defined message in catch block with respect to multiple exceptions in single catch block...
Ex:
}catch (IOException | SQLException ex) {
System.out.println("Exception thrown");
/**
* i want like this, if IOException is thrown then System.out.println("File not Found");
* if SQLException is thrown then System.out.println("DataBase Error");
*/
}
how to do this without using if-else block?
I have problem with my simple program. I tried put some text in my text area using button1 but textListener in RighButtons is always null and it's give me NullPointerException.
WriteToArea - interface
public interface WriteToArea {
public void add_a(String text);
}
BaseFrame
public class BaseFrame extends JFrame{
[Code] .....
There is a method taken from a class with several try and catch blocks. If you think it is possible, add one more catch block to the code to catch all possible exceptions, otherwise say 'Not possible' with your reason.
public String getCountyCode(Address inputAddress) throws AddressNormalizationException
{
String retval = null;
try
{
retval = this.normalizeAddress(inputAddress).getCountyCode( );
}
catch(InvalidAddressException e)
[code]...
In the following piece of code Iam confused as to where the InputMismatchException in the catch block is thrown on the first place? Is the InputMismatchException thrown automatically with declaring to throw the exception?
import java.util.*;
public class InputMismatchExceptionDemo {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
boolean continueInput = true;
[code]....
Is it a best practice to return from try block or place return statement after try-catch when we intend to return a value from a method(* Catch block is being also used to rethrow the exception)??
View Replies View RelatedRegarding return statements within methods. So I have a method containing try and catch block (as required) and much like when you have an if else statement... I noted you have to return an object for both the try and catch blocks. Now in my case my method should return a List object.
The way I have tried to overcome this:
- I've initialised a List object to null as an attribute of the class I'm working in.
- Therefore in the catch block would just simply return the null List object, where as the try block would return the non-empty List (which is what I want).
- I then just test to see if the List != null, when the method is invoked... and that is that.
However the method always seems to return null (when it shouldn't).
Any way to pass parameter between try/catch block.
In other word:
I have a method:
public void invia(OiStorto invioaca) throws Exception {
Long id=0L;
try {
//some code
for (VElenpere elenpere : elenperes) {
popolaScompiute(anno, inviaEOI0, param, opempiute, elenpere,id);
[Code] ....
And finally the method in which the error can occur (the method poputa is called for every id)
private void poputa(ElOpeIncType opereIncompiute, OpeIncType operaSingola, OiOpera opere) {
try {
//some code
} catch (NullPointerException e) {
e.printStackTrace();
//return id;
}
So method invia call the method popolaScompiute, inside popolaScompiute there is an iteraction through some id and for some id can occur an error; what i want is the getting the value of id in the first method invia, using the block try/catch. Is there a way to accomplish this?
consider this program :
public class hello {
/**
* @param args
*/
public static void main(String[] args) {
int s = new hello().h();
System.out.println(s);
} public int h(){
try{
int g = 10/0;
[Code] .....
the output is 7. how the flow is working. i understand that there is a divide by zero exception after which the control goes to catch. what about the return statement in catch . why is it overridden by finally..........
I want to use a try catch block, but I am not sure how to fix this problem:
int a;
try{
a = Integer.parseInt(A.getText());
}
catch (Exception e){
Output1.setText("Error");
}
//do someting with a here
The purpose of the try-catch is to catch blank input.The problem with this is that underneath the try - catch I get an error saying that the variable might not have been initialized. I know why this happens. I know I could initialize the varaible before the try - catch, but there is no default or null I can set an int as. If I initialized it as 0, the blank input will no longer be catched.how to make this problem disappear?
Right, so I got this program. It takes input from the user and assigns it to fields on an object. But, it's meant to check the users input. If the user enters bad input, it's supposed to throw this exception. For each of these exceptions, theres a class specifically for it.
public class PayrollDemo
{
public static void main(String[] args)
{
Payroll pr = new Payroll ("Test Name", 234);
System.out.println("Current Employee Information.
");
System.out.println("Name: " + pr.getName());
System.out.println("ID: " + pr.getID());
System.out.println("Hourly Pay Rate: " + pr.getHourlyPayRate());
[Code] ....
And this is the exception class.
public class InvalidNameException extends Exception
{
/**
No-arg constructor
*/
public InvalidNameException()
{
super("Invalid name");
}
}
PayrollDemo.java:43: error: cannot find symbol
InvalidNameException.InvalidNameException();
^
symbol: method InvalidNameException()
location: class InvalidNameException
1 error
It's just meant to tell the user that they entered an invalid value, which would mean if they entered an empty string instead of a name.
Overloaded methods CAN declare new or broader checked exceptions. We know that FileNotFoundException is a subclass of IOException and according to the above statement an overloaded method cannot throw a narrower exception. But the below code does not throw a compiler error. How?
Animal.java
Java Code:
package pack1;
import java.io.FileNotFoundException;
import java.io.IOException;
public class Animal{
public void drink(int s) throws IOException
{
}
} mh_sh_highlight_all('java');
[code]....
I hope I'm putting this question in the right folder. I have an array of objects, and I have defined a setter for a variable in the object. When I call the setter, I get a NullPointerException. Here is the relevant code for the object.
public class Digit extends Thread {
private int digit;
public void setDigit(int digit) {
this.digit = digit;
}
// run method follows
}
Here is the portion of the main class where I define an array and then call the setter.
Digit[] digits = new Digit[10];
for (int i = 0; i < digits.length; i++) {
digits[i].setDigit(i); // NullPointerException occurs here
}
I am creating a simple ArrayList program that would enable one to input their username to it using a scanner. However, i am getting this error: "Exception in thread "main" java.lang.NullPointerException
at home.Members.addUser(Members.java:16)
at home.Main.main(Main.java:14)"
Here is the code! :
Main.java class
Java Code: import java.util.Scanner;
public class Main {
[code]....
I have a enum class which contains some string which i am comparing to a string i get from a user
Java Code:
public enum Compare {
a, b, c, d, e, f
} class SomeClass {
String method(String letter){
Compare word= Compare.valueOf(letter);
}
} mh_sh_highlight_all('java');
Everything works fine but when I added a new word to it like "g" it throws the IllegalArgumentException ?
I have the following unit test that gives me a null pointer exception. The debugger goes to the finally block right after the line that creates a connection factory. Here's the test:
@Test
public void receiveMessage() throws Exception {
MessageConsumer consumer = null;
ConnectionFactory connectionFactory = null;
Connection connection = null;
Session session = null;
Destination destination = null;
[code]....
I am getting a nullpointer exception after "cleaning" up my code by putting repetitive stuff in a method.
The error points to this: ai.getItRight(n, answer);//make sure the user enters yes or no..
The error occurs at lines 19 and 25.Here is the relative code:
public boolean AskQuestions(Node n, String yesOrNo, String answer, String question){
if(yesOrNo.equalsIgnoreCase("no") && n.getRight() == null){//i guessed the wrong answer
System.out.println("I give up. Who is it: ");
answer = input.nextLine();
[code]....
My previous code, which use to have the contents of getItRight in place of lines 19 and 25 worked just fine. So why am I getting this error? I dont want my methods to be crazy big like how they usually end up.
So I have re-written the code but it is still not running correctly. Any number i type in it throws an exception, also i need the program to add the totals that i type in and then once i type -1 into the prompt button list all the number i typed in and give me the average.
import java.awt.*;
import java.awt.event.*;
import javax.swing .*;
import javax.swing.text.*;
public class Averages extends JFrame
{
//construct components
JLabel sortPrompt = new JLabel("Sort By:");
[Code] .....
I've got a nasty nullpointer that I have tried to resolve to no avail as of yet. The program should prompt for a listings.txt file and take its info and write to a report file. Here's the stacktrace:
run:
Input file: listings
Exception in thread "main" java.lang.NullPointerException
at java.io.Writer.<init>(Writer.java:88)
at java.io.PrintWriter.<init>(PrintWriter.java:113)
at java.io.PrintWriter.<init>(PrintWriter.java:100)
at kettask2b.PropertyListingsReport.main(PropertyListingsReport.java:34)
Java Result: 1
Some adjustments that I have attempted are:
BufferedWriter pwfo = null;
for (int i = 0; i < args.length; i++) {
String string = args[i];
pwfo = null;
[Code] ....
Here's the code:
package kettask2b;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
[Code] ....
I've come across an interesting problem when using a Jcombobox as a custom cell editor(and renderer) in a jtable. I was hoping to add a keybinding in order to display the dropdown of the combobox instead of having to click on it however, when I make a call to showPopup() I get:
Exception in thread "AWT-EventQueue-0" java.awt.IllegalComponentStateException: component must be showing on the screen to determine its location Which is strange as my jtable is visible and the editor/renderer seems to be working fine.
Here's the cell editor + renderer I'm using:
class MyComboBoxRenderer extends JComboBox implements TableCellRenderer {
public MyComboBoxRenderer(String[] items) {
super(items);
} public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected,
boolean hasFocus, int row, int column) {
if (isSelected) {
setForeground(table.getSelectionForeground());
[code]....
class Arg
{
public void rt()throws Exception
{
System.out.println("hi");
throw new RuntimeException();
}
public static void main(String args[])
[code]...
the way to handle the exception that has been in the catch block{b.rt()} .
I want to catch the exception in my program is the below way:
class Temp
{
public static void main(String s[])
{
try
{
int x=10/s.length;
System.out.println(x);
[Code] ....
I am expecting my program should give output as "java.lang.ArithmeticException: / by zero" but is giving
Temp.java:11: error: ')' expected
catch (ArithmeticException e | ArrayIndexOutOfBoundsException e)
^
Temp.java:11: error: ';' expected
catch (ArithmeticException e | ArrayIndexOutOfBoundsException e)
^
Temp.java:16: error: 'catch' without 'try'
catch (Exception e)
^
Temp.java:22: error: reached end of file while parsing
}
^
4 error
I want to write classes with methods that perform JDBC operations that throw SQL exceptions. For many of the methods, I'd ideally like to be able to have them catch exceptions and just send them to a standard Logging system "IF" the code that calls the methods is not going to catch the same exception. However, I'd like the "option" to have code that calls these methods catch the same errors if I want to but not "Require" the calling routines to catch them.... so I don't want to declare the methods with a "throws" that would require all calling code to Try/catch.
For some background, the logic behind what I'm looking to do is that there will be lots of places where these classes and their methods may be used where the code is basically "throw away" scripting code where just having error logs generated is more than sufficient. However there are also places I want to use the same classes/methods that I would want to handle the exception differently. So, for at least half the places I want to use these methods, there's no good reason to require cluttering the calling code with Try/catch, but when I DO want to handle the exceptions, I'd like them to get passed up to the calling routine so I can handle them in a way that is appropriate for the calling routine. Does that make sense?
I guess I'm kind of looking for is the ability to "override" the catch of a called method "IF" I want to but to treat the method as though it doesn't throw any exception "IF" I don't want to override the called routines catch logic.
Is this possible?
The requirement is to write a rectangle class and a test class, which include try-catch blocks and exception handling. Exceptions, involving try, catch, throw, throws, and finally commands,how to write a code about basic things, but in the test class, it gives me specific width and height so that i dont konw how to write a try-catch blocks an exception handling in this test class.There is my two classes, they are separated.
public class Rectangle {
double width ;
double height ;
Rectangle(){
width = 1;
height = 1;
[code]....