class MultipleReturn {
int getInt() {
int returnVal = 10;
try {
String[] students = {"Harry", "Paul"};
//System.out.println(students[5]); //if i remove comment
[Code] .....
I know I can calculate the sum of squares as such:
// SumSquares.java: calculate the sum of two squares
class SumSquares {
static int sumSquares(int a, int B)/>/> {
int asquare;
int bsquare;
[Code] .....
But how can I modify the code so that it inputs a list of integer values in the range of -100 to 100 from the keyboard and computes the sum of the squares input values. And how would I go about using exception handling to ensure that the input values are in range and are legal integers.
I have studied about the hierarchy of exception classes in which Throwable class comes at the top and two of its direct subclasses are Error and Exception..I just want to ask if in some code snippet we throw an instance of Error or its subclass within the try catch block then will that be also called "exception handling" ? I am asking this because Error class is not a child class of Exception therefore cant be said an Exception, therefore handling the same should not be called exception handling
View Replies View RelatedI was giving a quick skim to some tutorials on the internet where I have found the exception that is handled is also declared in the throws clause of the method wrapping the try-catch block. For a code representation consider the following:
public void methodName() throws IOException {
try {
...
} catch (IOException ex) {
.... TODO handle exception
}
}
When I am watching scjp mock test, I am getting error about security.
I am trying to add www.javaranch.com to site exception list in java control panel. I can see security tab in java control panel, there I find field for Site Exception List. When I am add [URL] .... to this site exception list, list is not getting populated.
Why is that ? Why am I unable to add this site to list ?
I am using 64-bit system and have downloaded and installed 64 bit update patch 51.
Is there any connection between packages and exception handling in java. Means is it necessary to create a package before trying exception handling examples?
View Replies View RelatedIs there a special mechanism through which exception can be handled in a constructor?
Suppose while creation of an object there occurred an exception while creating an object, and the object is half constructed. How do we make sure we handle this kind of exceptions in a constructor?
For one of my last labs for the semester, my professor is having the class go back to our very first program and apply some of the exception handling that we just recently learned about. Here's my improved code so far:
Java Code: import java.util.*;
import java.lang.*;
public class Lab2Part1 {
public static void main (String [] args) {
Scanner input = new Scanner (System.in);
[code]....
My code compiles fine, but even if I enter an integer or a double, it saves the number as a string, and prints that out as the name. Is there any way to get around this? Or do I need to use something besides a try-catch?
I have been working on a problem dealing with exception handling and text input output for a few days now. The exercise is a two part exercise. The first part of the exercise I have to write a program to display the total salary for assistant professors, associate professors, full professors, and all faculty, respectively, and display the average salary for assistant professors, associate professors, full professors, and all faculty, respectfully using the what is posted on the [URL] .... Each line in the file consists of a faculty member's first name, last name, rank, and salary. The second part of the exercise I have to take my code and change it so that it
-lets the user enter the name of the file to be read,
-Uses a try-catch block to handle the FileNotFoundException displaying instead The file already exists..
... Use a second catch block to ignore any other exception thrown.
... Design your code so that, if the user enters a file that does not exist, the program prompts the user to enter again a file name.
and I need to Note: In order to catch the FileNotFoundException, you need to include import
java.io.FileNotFoundException;
package pkg14.pkg25;
import java.util.Scanner;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
[code]...
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 RelatedI want to use my given code as base class
Java Code:
public static void file(String[] arg) throws IOException{
BufferedReader in;
String line;
try{
System.out.println("Reading word");
in =new BufferedReader(new FileReader("inp.txt"));
[Code] .....
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?
I know I can calculate the sum of squares as such:
// SumSquares.java: calculate the sum of two squares
class SumSquares {
static int sumSquares(int a, int B)/>/> {
int asquare;
int bsquare;
[Code] ....
But how can I modify the code so that it inputs a list of integer values in the range of -100 to 100 from the keyboard and computes the sum of the squares input values. And how would I go about using exception handling to ensure that the input values are in range and are legal integers.
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]);
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?
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]....
I am trying to learn how to use file input/output in addition to exception handling... The problem is my textbook wrote this chapter for a version of Java that hasn't come out yet, so everything I do "according to the textbook" doesn't work. any feedback on correcting these exception errors because I am not sure what is causing them or how to fix them.
I was able to have it display the name of the book in the Book.txt file, but when I added the second part if the file doesn't exist, that's when the errors came up and it wouldn't compile.
import java.io.*;
import java.util.*;
public class DisplayBook
{
public static void main(String[] args) {
try {
File book = new File("Book.txt");
FileInputStream in = new FileInputStream(book);
[Code]...
These are the compilation error messages I am receiving: (I have managed to get it down from 7 errors to just 4, but now I'm stuck)
DisplayBook.java:15: error: unreported exception IOException; must be caught or declared to be thrown
while ((letter = in.read()) != -1) //if file exists, displays book title
^
DisplayBook.java:24: error: unreported exception FileNotFoundException; must be caught or declared to be thrown
[Code] ....
4 errors
This program is basically complete. It compiles and runs. It is a college course assignment that I pretty much completed but for the last part in which I'm suppose to change the values of all fields and display the modified values using a toString method. Modifying the values of the fields is where I am stuck. I don't think I need to create a new text data file to do this. The instructor only asked that all the values of fields be changed and this was the last part of the assignment so I don't think it involves creating additional ObjectOutputStream and ObjectInputStream objects. I'm getting a NullPointerException error on line 161.Here is the code. I'm also including the input data file.
//create program so that objects of class can be serialized, implements interface Serialiable
//create constructor with 4 parameters with accompanying get and set methods, Override toString method
//create text file with 5 records, create Scanner object,ObjectOutputStream, and ObjectInputStream
//create new ItemRecord object, change values of all fields in ItemRecord object using object's set methods
//modify ItemRecord object using toString method
[hightlight =Java]import java.io.Serializable;
public class ItemRecord implements Serializable
[Code] .....
This is the error message:
----jGRASP exec: java ItemRecordReport
Item Cost Quantity Description
Number
A100 $ 99.99 10 Canon PowerShot-135
A200 $149.99 50 Panasonic-Lumix T55
A300 $349.99 20 Nikon- D3200 DSRL
A400 $280.99 30 Sony- DSC-W800
A500 $ 97.99 20 Samsung- WB35F
Exception in thread "main" java.lang.NullPointerException
at ItemRecordReport.main(ItemRecordReport.java:161)
----jGRASP wedge2: exit code for process is 1.
----jGRASP: operation complete.
Here is the data file:
A100 99.99 10 Canon PowerShot-135
A200 149.99 50 Panasonic-Lumix T55
A300 349.99 20 Nikon- D3200 DSRL
A400 280.99 30 Sony- DSC-W800
A500 97.99 20 Samsung- WB35F
Here is the data file for the modified field values.
B100 98.00 10 ABC1010
B200 97.00 15 DEF1020
B300 96.00 10 GHI1030
B400 95.00 05 JKL1040
B500 94.00 01 MNO1050
I have written the following code to calculate tax payments based on income and filing status :
import java.util.Scanner;
public class computeTax {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
// prompt for filing status
System.out.println("enter '0' for single filer,");
[Code] ....
The while loop initiated on line 21 is there so that in case the wrong input is given at the prompt given in line 24, the program outputs "please type the right answer" with the command on line 254 before looping back to line 24 and prompting the user to enter his status number. The program works as long as the input at line 28 is an integer. Not surprisingly if the erroneous input here is not an integer, the program outputs the following error message :
Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Scanner.java:909)
at java.util.Scanner.next(Scanner.java:1530)
at java.util.Scanner.nextInt(Scanner.java:2160)
at java.util.Scanner.nextInt(Scanner.java:2119)
at computeTax.main(computeTax.java:28
To try to solve this I used the Try / Catch technique with the following version of the code :
import java.util.Scanner;
public class computeTax {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
// prompt for filing status
System.out.println("enter '0' for single filer,");
[Code] ....
int nRows = 0;
for (EITest testCurr : testList) {
testCaseListArray[nRows] = new Object[3];
String testName = testCurr.getTestName();
LOG.info("testName=" + testName);
testCaseListArray[nRows][0] = testName;
[Code] ....
This throws null pointer exception because of array initialization error. I tried this:
int nRows=0;
for(EITest testCurr: testList){
testCaseListArray[nRows] = new Object[3];
String testName = testCurr.getTestName();
LOG.info("testName=" + testName);
testCaseListArray[nRows][0] = testName;
[Code] ....
But this is not complete solution.
2) I want to make this as a collection object such as array list instead of Array declaration.
Why the following is happening.
For the below code, when I execute it, it prints
Short method 10 //result 1
Sub class short method 10 //result 2
Which is as expected but if I comment out line 3, then it prints
Integer method 10 //result 3
Integer method 10 //result 4
I can understand result 3 is because of an upcast from short to int, since FunWithOverloading will not have a overloaded method with short now. However, what is happening with result 4? Shouldn't it call methodA of the subclass with the argument type short? If its because I have declared the reference variable, derived, of the type FunWithOverloading, then how come the first result correctly picks the overloaded method of the sub class?
class FunWithOverloading{
void methodA(int x){System.out.println("Integer method " + x);}
void methodA(short x){System.out.println("Short method " + x);} //line 3
} class OverloadedSubClass extends FunWithOverloading{
void methodA(short x){System.out.println("Sub class short method " + x);}
[Code] ....
I have having some trouble on counting the primitive operations on the pseudocode given below:
Algorithm 4. MaximumArray(Arr)
Input: A 1-D numerical array Arr of size n
1) Let CurrentMax = a0
2) For i = 1 to n-1
3)If ai > CurrentMax Then CurrentMax = ai
4) End For
Output: CurrentMax, the largest value in Arr
As of now, I know that for Line 1 there are 2 operations (one set and one read). I don't know how to figure out the for loop and If statement (line 2 and line 3 too).
I've got a question to ask.
public class AutoBoxingExample {
public void add(Integer intVal){
System.out.println("Wrapper");
}
public void add(int value){
System.out.println("Primitive");
}
public static void main(String[] args) {
AutoBoxingExample auto = new AutoBoxingExample();
auto.add(12);
}
}
The output is "Wrapper". What would be the reason behind it?
Is it possible to check to see if a what a user has entered is a string or a other variable type, if I'm asking this the right way?
View Replies View RelatedWhy is it necessary to implement the comparable interface for primitive types and not for classes such as Integer, String etc . . . ?
View Replies View RelatedI am totally new to Java. What is the purpose of this method?
Flow of the int x=3; like where does the 3 go step by step?
Passing Primitive Data Type Arguments (from oracle java tutorials)
Primitive arguments, such as an int or a double, are passed into methods by value. This means that any changes to the values of the parameters exist only within the scope of the method. When the method returns, the parameters are gone and any changes to them are lost. Here is an example:
public class PassPrimitiveByValue {
public static void main(String[] args) {
int x = 3;
// invoke passMethod() with
// x as argument
passMethod(x);
[Code] ....