Check To See If Entry Is Either Primitive Or String?
Feb 5, 2015Is 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?
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Converting Long (primitive Type) To String?
Nov 2, 2014I have to use a long primitive type for the input of a credit card number and ID the credit card by using the first number of the input; however, the only way I know for that is to use charAt, which is used for a String. Is there a way to convert long to String, or am I missing a better solution? (There's no code because I'm still doing the pseudocode).
View Replies View RelatedHow To Check If At Least One Number In A String Is Different From 0
Nov 18, 2014I'm trying to come up with a method that would validate each turn a player makes. For a turn to be valid, it has to only contain numbers from 0 to 3(inclusive) and at least one digit must not be 0. Here is what I`ve come up with so far. For example, with "303" as the number and "101" as the turn, the turn would be valid and my method should return true, but it does not.
public static boolean turnIsValid (String number, String turn ){
boolean rep=false;
int pos1=0;
char min='0';
char max='3';
while(number.length()==turn.length()&&pos1<turn.length()){
[Code] ....
Check How Many Times Char Is Used In The String
Apr 1, 2014I tried to make a program that takes a string str, and char a and checks how many times the char is used in the string.
Example: the string Welcome and the letter e, is 2 times. so the program should print 2.
It compiles but when I run it and enter the information, i cannot get the printing line out.
Heres my code:
import java.util.Scanner;
class program
{
public static void main(String[] args) {
Scanner user_input=new Scanner(System.in);
String str;
String b;
System.out.print("Please enter a word");
[Code] .....
Check If A String Array Is Sorted?
Jul 8, 2014I have an assignment and one of the prompts is to do a binary search on an array if and only if the array of Strings is sorted. The binary search part I think I have completed, but it is the sorted array check that is throwing everything off. If the array is already sorted, return true; else, return false.
// Check if the array is sorted
public static boolean isSorted(String[] arr) {
//for (int i = 0; i < arr.length-1; i++)
//{
//if (arr[i].compareTo(arr[i+1]) > 0)
//return false;
//}
String[] arrSorted = arr;
Arrays.sort(arrSorted);
[code]....
How To Check If ArrayList Of Object Contains A Certain String
Mar 25, 2015I have a number of objects stored in an ArrayList called inventory. Let's say I have two objects inside.
inventory.add(new Lamborghini(2011, "aventador", 411.3, false));
inventory.add(new Lamborghini(2012, "sesto elemento", 512.3, true));
I am making a function to search through the whole inventory to see if any of the Lamborghini object has a certain model name such as aventador, diablo, etc....
This is what I have but I figured there's a big mistake when I make it true / false; it's making it going through the list and what's return is the last one instead of saying there's such match in the whole list or not.
public boolean hasCarModel(String modelName){
boolean exist = false;
for (Lamborghini lambo : inventory){
String carModelName = lambo.getModelName();
if(carModelName.equalsIgnoreCase(modelName)){
[Code] ....
I figured if I add break; under exist = true; it'll work because as soon as it found one match then it'll turn to true and break out the loop but I don't think this is the best way to do it right?
Check If A String Is A Palindrome By Using Stacks
Oct 23, 2014I'm supposed to use stacks (implemented with an array) to check to see if a string is a palindrome. I've finished all my classes and methods, but I'm getting an ArrayIndexOutOfBoundsException when I try to run my demo program.Here are my classes:
public interface Stack {
// Creates an empty stack
public void initializeStack()
// Returns true if the stack is empty, returns false otherwise
public boolean isEmpty();
// The stack can never be full, so always return false
public boolean isFullStack();
[code]...
Check How Many Times Char Is Used In String
Apr 1, 2014I tried to make a program that takes a string str, and char a and checks how many times the char is used in the string. Example: the string Welcome and the letter e, is 2 times. so the program should print 2. It compiles but when I run it and enter the information, i cannot get the printing line out.
Heres my code:
import java.util.Scanner;
class program
{
public static void main(String[] args) {
Scanner user_input=new Scanner(System.in);
String str;
String b;
System.out.print("Please enter a word");
str=user_input.next();
[Code] ....
How To Check A String For NON-Alphabetic Characters
Oct 2, 2014I have to check a String input from the user in the form of firstName lastName (i.e. John Smith). I have to check for an exception called NonAlphabeticCharacterException that gets thrown if there is anything but a number in that string. This is what I have right now but should I create an array of char for the alphabet and then check the whole string for non alphabetic characters?
for(int i=0; i<name.length(); i++) {
if()){
throw new NonAlphabeticCharactersException("Non-alphabetic character found");
}
}
String Declaration - Check A / B Returns False
Jan 30, 2014I have doubts in string declaration. As I know we can declare string in two ways:
1. String a=new String("Hello");
2. String b="Hello";
What is exact difference between them? Another thing is when I check (a==b) it retuns me false, but when I check a.equals(b) it returns me with true. Why So?
How To Check String For Exactly 2 Capital Letters And 1 Space
Jul 23, 2014I started using Java a couple of days ago, If you haven't guessed I want to see if the user is typing a full name or not, but I'm actually not too concerned with any more complexity than I mentioned in the title. It's ok if an input like "GLba b" comes out positive.
View Replies View RelatedHow To Check For A String In The File And Get Start And End Line Numbers
Aug 13, 2014write the logic in the below given Java method.
Public static boolean updateNetMap(String filepath, String nodename){
// check the file pointed by filepath to have entry for nodename.
// if it is there, get the start line no and end line no
// Based on the line nos, need logic to remove the contents from the file.
}
Below is the sample node entry, which we need to identify and delete (here nodename is WAS_CD1):
WAS_CD1:
:conn.retry.stwait=00.00.00:
:conn.retry.stattempts=6:
:conn.retry.ltwait=00.00.00:
:conn.retry.ltattempts=6:
:tcp.max.time.to.wait=0:
[Code]...
How Selected Radio Button Of Text Check With Another String Of Array
Jun 20, 2014Java Code:
ButtonGroup bg=new ButtonGroup();
JRadioButton choice1=new JRadioButton();
JRadioButton choice2=new JRadioButton();
JRadioButton choice3=new JRadioButton();
JRadioButton choice4=new JRadioButton();
bg.add(choice1);
bg.add(choice2);
bg.add(choice3);
bg.add(choice4); mh_sh_highlight_all('java');
here i coded out my radio button..i am confused how to get the selected radio button of string and match with another array of String..
String Analyze - Take A Sentence And Check How Many Times Specific Words Come Up
Sep 8, 2014Basically the requirements are to take a sentence (string of text) and check to see how many times specific words come up and then add to the counter depending on the word.
But I can not seem to get it to add the instances of the goodwords and badwords.
package Strings;
import java.io.*;
public class SentimentAnalyser {
private static String analyse(String text) {
int pw = 0;
int nw = 0;
String[] searchword = { "bad", "terrible", "good", "awesome" };
[Code] ....
Manually Add Exception Table Entry?
Apr 8, 2014because of the need to implement a certain software watermarking technique I have to manipulate the exception table.
(Link to the paper that describes the technique: [URL] .... (Section "Extension to Java Bytecode")
So far I could manually add the exception table entry with Javassist:
MethodInfo minfo = (MethodInfo) aclasscf.getMethods().get(0);
CodeAttribute ca = minfo.getCodeAttribute();
ExceptionTable et = ca.getExceptionTable();
[Code]....
Swing/AWT/SWT :: Restricting Data Entry In TextFields
Mar 4, 2015I'd like to know is there a way to restrict a user from inputting certain characters into a TextField? Is there something like isNumeric() available?
In Visual Basic, I was able to prevent the user entering certain characters of my choice into each textbox, however I've looked and I haven't been able to find a solution. I've tried using the following else if as part of an if statement:
else if (txtEmployeeName.getText().contains("[0-9]+"){ }
but it doesn't seem to work.
Servlets :: Null Retrieved From Env-entry Resource
Jan 9, 2009I have an env-entry defined in my web.xml and when I attempt to print it from a simple servlet all I get is null. And of course if I attempt to invoke any methods on the object I get a NullPointerException.I read somewhere that this can happen if you're using version 2.4 instead of 2.5, so I changed to 2.5 and I still have the same issue. Here's the web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.5"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_5.xsd">
<display-name>ResourceTest</display-name>
<servlet>
[code]....
Adding Entry To PATH Variable In Bin Directory
Dec 24, 2013I'm using Ubuntu. After unpacking the tar file for JSE 1.7 version 45, in the the bin directory for adding an entry to PATH variable, I typed
javac
and I get the message
The program 'javac' can be found in the following packages:
* default-jdk
* ecj
* gcj-4.6-jdk
* gcj-4.7-jdk
* openjdk-7-jdk
* openjdk-6-jdk
Try: sudo apt-get install <selected package>
Do I have to install these ?
Manually Adding Exception Table Entry
Apr 7, 2014I use Javassist to manually add a exception table entry:
Java Code:
MethodInfo minfo = (MethodInfo) aclasscf.getMethods().get(0);
CodeAttribute ca = minfo.getCodeAttribute();
ExceptionTable et = ca.getExceptionTable();
et.add(26, 30, 40, 0);
System.out.println("exception table size: " + et.size()); mh_sh_highlight_all('java');
If I get the bytecode with javap it seems to work:
Java Code:
Exception Table
from to target type
26 30 40 any mh_sh_highlight_all('java');
But the problem is that I can't run the file anymore. Simply running it with the java command results in "java.lang.VerifyError: Expecting a stackmap frame at branch target 40". After some research this seems to be a problem with java 7 and a stricter verifier. I read several times that java -XX:-UseSplitVerifier should be used instead.
This really fixed the stackmap error, but then another error appeared: "java.lang.VerifyError: (class: AClass, method: signature: ()V) Inconsistent stack height 2 != 1". Are there any further steps required to insert a new exception in the exception table?
Additional info: Later I want to remove gotos (in this case the goto at line 27) and add a function call instead. When this function finishes it will throw a exception and propagate it back to the caller (which will be at line 27). Then the program should go on as if nothing happend, that is also the reason why the target of the exception is the same as the target of the goto (40)
Here is the bytecode:
Java Code:
0: aload_0
1: invokespecial #8 // Method java/lang/Object."<init>":()V
4: iconst_0
5: istore_1
6: goto 19
9: getstatic #10 // Field java/lang/System.out:Ljava/io/PrintStream;
12: iload_1
13: invokevirtual #16 // Method java/io/PrintStream.println:(I)V
[Code] .....
Exception table:
from to target type
26 30 40 any mh_sh_highlight_all('java');
JSF :: Finding Index Of Entry In ArrayList - Select Item
Oct 2, 2014I have a JSF application with this code in the xhtml page:
<h:selectOneListbox id="selectProduct" size="10" style="width:10em; font-family:monospace" value="#{mybean.product}">
<f:selectItems value="#{mybean.products}" />
</h:selectOneListbox>
and the corresponding snippets of the Java code are:
// Class member variables
// ...
private String product;
private ArrayList<String> productValues;
private ArrayList<String> productLabels;
private SelectItem[] products;
// ... Various properties etc.
public String getLocation() { // Displayed on a page
[code]....
Most of this works correctly using only ArrayList SelectItem products without the two ArrayList and the separate SelectItem[], and the values and labels are put directly into products here. The menu works and I can select an item. However, I am unable to find the correct method for finding the index in the submit method,namely:
public void submit(ActionEvent e) {
showProduct = true;
prodNum = products.indexOf(product); // --- Here is the problem!
updateProduct();
}
which has not been changed here. In spite of trying out various ideas, prodNum always returns with -1, which means it cannot find the index of the selected product, where product is a String. Everything else seems to work correctly, and products.get(prodNum).getLabel() works if I manually give prodNum a valid index, but because it's -1 it fails.
Launch Windows Directly Into JAVA Based Password Entry System?
Apr 5, 2014 Is it possible to launch windows, specifically 8.1, directly into a java based program which would serve as the password entry screen? That is to say, instead of using the standard windows screen, could a java based alternative be used?
I have the source code used on jurassicsystems.com. I would absolutely kill to have a tweaked version of this system act as my password entry screen. It is literally something Ive wanted to have done for ages, and this emulation finally means it may be possible.
Overloading With Primitive Types?
Jan 22, 2015Why 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] ....
How To Count Primitive Operations
May 2, 2014I 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).
Wrappers And Primitive Types
Feb 23, 2015I'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?
Comparable Interface For Primitive Types
Apr 16, 2014Why is it necessary to implement the comparable interface for primitive types and not for classes such as Integer, String etc . . . ?
View Replies View RelatedPassing Primitive Data Type Arguments
Jun 5, 2014I 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] ....