Returning In Methods With Try Catch Block
Feb 18, 2015
Regarding 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).
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Jan 15, 2014
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]...
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Sep 19, 2014
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]....
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Apr 13, 2015
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)??
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Oct 14, 2014
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?
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Jul 2, 2014
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..........
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Jul 16, 2014
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.
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Feb 28, 2015
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?
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Feb 2, 2015
import 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?
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Sep 15, 2014
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]);
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Oct 26, 2014
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?
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May 5, 2014
So I'm pretty sure this is correct, as it follows most examples I can find online, but I keep getting an error that my return variable cannot be resolved. The error is on the return conn; statement. It says conn cannot be resolved. If I place it above within the try block it allows it but then I receive an error saying the method getDBConnection must return type Connection.
import java.sql.*;
public Connection getDBConnection() {
try {
Class.forName("org.sqlite.JDBC");
String path = "jdbc:sqlite::resource:project.db";
[Code] .....
I don't want to create this method. Basically I want to connect to the database in the main program, but I do want methods that can access the DB too. But however I place it, it doesn't let me touch any of the DB variables outside of the Try block.
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Sep 24, 2014
The code is below. The program runs a series of calculations based on data input by the user. My problem is that for the most important thing I'm looking for, total kg CO2 emissions, I continually get an answer of 0.0. What I need is a sum of the individual total emissions as calculated in each method, i.e. the values which are printed with the following: System.out.println(trans); System.out.println(elec); and System.out.println(food);
The total should be something like 25040 or whatever, depending on the value of the inputs provided by the user, but I'm constantly getting a total of 0.0., which is obviously false. Could have something to do with the way I've initialized my variables, or something to do with the limitations of returning values from methods.
import java.util.Scanner;
public class CarbonCalc {
public static void main(String[] args) {
double trans = 0;
double elec = 0;
double food = 0;
giveIntro();
determineTransportationEmission(null);
[code]....
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Jan 23, 2015
I'm writing a program that involves the use of set/get methods. I will submit a sample code of my issue. The format appears to be alright however the program is not returning any data. This is the same format as my actual code. Why this might be happening?
Java Code:
public static void main(String [] args) {
SecondClass object = new SecondClass();
object.setName("Name");
object.getName();
} mh_sh_highlight_all('java');
Java Code:
public class SecondClass {
private String name;
public SecondClass(){
name = " ";
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
} mh_sh_highlight_all('java');
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Feb 4, 2015
I have a very standard Lab assignment. It's probably been seen a lot. I wrote the first part not realizing I had to write a second class to do use the methods. I'm not sure how to change my program to call methods from my second class instead of doing all my calculations with user input in my first class.
Here's the first class' code:
package tickets;
//Imports classes used for "Ticket" application.
import java.util.*;
import java.text.DecimalFormat;
public class Tickets {
[Code] ......
The code is obviously incomplete. I have not tried to compile, nor would I expect it to compile right. I'm not sure how to move my calculations from the first class shown above into my second class and use them as methods.
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Oct 8, 2014
I am stuck on this part of my assignment. When the answer prints out at the end, the calculation of average is incorrect. This is what the assignment wants:
Write two overloaded methods that return the average of an array with the following headers:
public static int average(int[] array)
public static double average(double[] array)
Write a test program that prompts the user to enter ten double values, invokes this method and displays the average value.
public class Week7Arrays2 {
public static int average(int[] array) {
int sum = 0;
int average = 0;
for (int i = 0; i < array.length; i++) {
sum = sum + array[i];
[code]....
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May 24, 2015
The question pretty much says it all, but I tasked myself with creating a program about lemurs. There are multiple class files in this program. In the below code snippet, I have my TreeLemur.class which extends to the Lemur.class which extends to the Mammal.class. However, when I create a Tree Lemur object in the main program, it is returning null consistently from certain methods. What am I doing wrong here?
TreeLemur.class :
public class TreeLemur extends Lemur {
private String groupSize;
private String diet;
private String fur;
public void setGroupSize() {
groupSize = "
Group Size: Large";
}
[Code]...
As of yet, I'm just trying to get Tree Lemur working properly to continue with creating the other if-branches within the main program.
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Jun 9, 2014
I wrote a program using switchcase.I used do while to show the menu to the user until the user decides to exit the menu.I used try catch to prevent ant exception and it worked properly.But i got one problem.When exception occurs,desired msg is printed but i am unable to display the menu to the user.So user wont be able to continue after an exception is caused.
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Feb 3, 2015
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()} .
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Nov 7, 2014
public class ThrowException {
public static void main (String[] args) {
var x=prompt("Enter a number between 0 and 10:","");
try {
if (x>10){
throw "Err1";
} else if (x<0){
throw "Err2";
} else if (isNaN(x)){
throw "Err3";
}
}
catch(er){
[code]...
It's telling me where catch(er) is: <identifier> expected..I've watched videos, but no one seems to encounter this error....am I missing a segment of code?
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Oct 15, 2014
I'm asking if there is a way to pass parameter between try/catch block.
I have a method:
public void invia(OiStorto invioaca) throws Exception {
Long id=0L;
try {
//some code
for (VElenpere elenpere : elenperes) {
[Code] ...
The method called in the for:
private void popolaScompiute(Long anno, InviaEOI inviaEOI0, _4IntegerType param, ElOpeIncType opereIncompiute,
VElencoOpere elencoOpere,Long id) {
try {
//some code
for (OiOpera opere : oiOpere){
[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 iteration 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?
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Apr 27, 2014
I've been assigned to write a program that will convert binary to decimal that uses the try/catch block. In the program that I have written, I was wondering if it is possible to write an addition catch statement that will present an error if any number other than a 0 or 1 is entered by the user. I have already done this in the binaryToDecimal method, but I am just messing around to see if it is, in fact, possible.
Java Code:
import java.io.IOException;
import java.util.Scanner;
public class BinaryToDecimal {
public static void main(String[] args){
Scanner input = new Scanner(System.in);
[Code] .....
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Jan 29, 2015
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
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Feb 20, 2014
I have used FileInputStream class but its not working properly to divide the bits into blocks.I will attach the coding
public static void main(String[] args) {
ReadFileExample newclass = new ReadFileExample();
System.out.println("cryptography");
[Code].....
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Dec 8, 2014
I'm trying to place a try/catch into a Actionlistener that will detect other characters other than alpha.
private class printbuttonHandler implements ActionListener {
public void actionPerformed(ActionEvent e) {
//Object src = namesinput;
//String message = "Insert Message Here";
notesinput.setText("");
JOptionPane.showMessageDialog(null, notesinput, "Receipt",
JOptionPane.PLAIN_MESSAGE);
}
I'm not even sure if I'm trying to place it in the correct area in the code. However I like to perform this prior to the receipt being displayed so if there a issue the user can correct this before the final receipt has been sent .......
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Jan 22, 2014
Right now we are learning about arrays and using the try/catch. Code below, I am trying to just display information about buildings. The application is good but not with the try and catch statement. I'm trying to just display the message of "please enter a building number" when a user puts a letter instead of a number(InputMismatchException) and then the user would have to put in one of the numbers. But when it runs and i put in a letter, it reads the message, but it always outputs the first building information ...
package username;
import java.util.InputMismatchException;
import java.util.Scanner;
//TallBuildings
public class TallBuildings {
//compare heights of buildings
[Code] .....
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