Difference Between Stringbuilder And String Buffer
Apr 3, 2014what is the difference between stringbuffer and string builder?
View Replies
ADVERTISEMENT
Trim In StringBuilder And String?
Feb 1, 2015I have a question about an exercise of OraclePress.
public class OompahLoompah {
public static void main(String[] ar){
final StringBuilder str = new StringBuilder("I good! ");
str.insert(2, "look ").append("and nice");
str.insert(str.length(), "!!!");
str.delete(str.length() - 2, str.length());
System.out.println(str.toString().trim());
}
}
The correct output is "I look good! and nice!" , but i don't understand for what .
Why the trim () method does not work? Whether is working on an object String.
C Buffer To Java String
Sep 4, 2014Due to compatibility reasons, I need to be able to store a random C buffer inside of a Java String. THis means that the Java String should contain the exact same buffer information (i.e. byte sequence) as the original C buffer. How would I do that?
All the functions I found will always somehow code/decode the C buffer, and modify its content depending on the selected encoding.
I need to do this inside JNI. Following is what I have:
Java Code:
unsigned char* cBuffer=getCBuffer();
// Transfer the C buffer to s:
jstring s=NULL;
if (env->EnsureLocalCapacity(2) >= 0)
{
jbyteArray bytes = env->NewByteArray(signalLength);
if (bytes != NULL)
[Code] ....
String Buffer Append Method
Feb 17, 2014I have the following code which always gives me java heap space error because of line number 65 due to string buffer append method in this line, I don't know why?
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
import samy.*;
import java.util.Scanner;
public class InfixToPostfix {
OrderedList list = new OrderedList();
Scanner input = new Scanner(System.in);
public StringBuffer postfix = new StringBuffer();
[Code] .....
Using String Tokenizer And Buffer To Decode A Message?
Apr 15, 2014So I have this file in which has a few sentences on a single line. What I need to be able to do is read the file and then take each word and create a token out of it. Then what it does is it selects the first letter of every 5th word, uppercase it, and then allow me to use append it via a stringbuffer object to create a word out of it.
I know I'll need to use a string tokenizer but I'm not sure how to do so in a way that makes each word separate and how to tell it to only hit the 1st letter of every 5th word.
Here's what I've come up with so far, but I'm currently at a loss at what to do and my textbook/documentation is just not working.
Java Code:
String line; // The line we read from the file.
char letter; // The first letter of each 5th word.
String sw; // The completed string.
public static void main (String [] args)throws IOException {
[Code] ....
Difference Between String And String?
Apr 27, 2015What is the difference between string and String (note the case)
View Replies View RelatedMethods Of StringBuffer And StringBuilder Are Identical
Apr 4, 2014" In terms of methods supported by the classes, the methods of StringBuffer and StringBuilder are identical. They only differ in whether the methods are synchronized or not. " - Oracle Certified Associate Java SE7 Programmer Study Guide
What does synchronized mean in this context?
StringBuilder - Replacing Each Letter Without Reverse Tool
May 28, 2014How can I replace each letter for example "abcde" to "edcba" with StringBuilder only and without the reverse tool. This is what I tried:
StringBuilder str=new StringBuilder("abcde");
int indexBegin=0;
int indexEnd=4;
for(int i=0;i<str.length();i++){
str.setCharAt(i, str.charAt(indexEnd));
indexEnd--;
}
System.out.println(str);
The output is:edcde with i understand why its wrong ,the last two letters already swap so it didnt take from the original str.
JOptionPane And StringBuilder - Display And Receive Information To / From The User
Mar 6, 2014I'm using the JOptionPane to display and receive information to/from the user. In addition to this, I am using StringBuilder to receive inputs from the user and then manipulate (append) that input to display the desired output.
//Example
(JOptionPane): "Enter text"
(user input): Java is cool!
(program): *stringBuilder.append(" I love it!")
JOptionPane.showMessageDialog( );
.....
Psuedo-like code. The problem is that showMessageDialog(null, string) and not showMessageDialog(string, string). I want to display the enter text: " Java is cool! I love it! " in the JOptionPane. How do I accomplish this, since showMessageDialog only accepts (null, string).
How Does A Buffer Reader Work
Mar 5, 2014a buffer reader , how does it work and what is the code for it ?
View Replies View RelatedSending XML Records To Sax Parser Using Buffer
Mar 26, 2014i am having a below piece of code in my worker thread. In my output i am getting xml records from the database. I'm sending this output to a input stream & finally to a sax parser.My query is, before sending to the parser i need to store the input stream in buffer. The buffer should store 1000 records. For every 1000 records the parser should be called from buffer.
while (orset.next()) {
output = orset.getString("xmlrecord");
writeCount++;
InputStream in = new ByteArrayInputStream(output.getBytes("UTF-8"));
InputStream inputStream = new ByteArrayInputStream(output.getBytes("UTF-8"));
Reader reader = new InputStreamReader(inputStream,"UTF-8");
[code]....
Swing GUI Freezing With Bounded-buffer
Jul 12, 2014I'm writing a simple application, that provides a Swing GUI to a bounded-buffer problem. The application is composed by:
- Main.java: it creates a map of four threads (four instances of the class MyThread). Also it creates a shared database (an instance of the class Database) between the four threads.
- MyThread.java: it's an extension of Thread, and it shows a Swing GUI associated to this thread. Each thread is associated a GUI.
- GUI.java
- Database.java: it's an extension of ArrayList and and it can contain a maximum of five elements. An element is an instance of the class User. Also it implements put() and extract() method consistent with the algorithm of bounded-buffer problem.
- DatabaseException.java: it's a simple message.
- User.java
public class Main {
public static void main(String[] args) {
Database db = new Database();
Map<String, Thread> tdg_m = new HashMap();
for (int i = 1; i <= 4; i++) {
tdg_m.put("T" + i, new MyThread(db));
[Code] .....
The issue is the following. When the database is full, and i try to put an element, the GUI freezes. The same problem occurs when I try to extract an element from the empty database.
Smoothing Input Using Ring / Circular Buffer?
Aug 11, 2014Normally I would just implement a circular buffer and be happy but there's a fundamental problem with that.OK, so I'm working on a piece of cheap Android hardware that's being used for demo purposes. One of the problems, primarily because it's cheap (imo) is that the screen input is not clean and is interfering with the UI experience. Specifically when gliding your finger, the result is quite non linear.
I know that's not the best drawing but it sort of explains the problem to a degree. In reality, it's probably a bit smoother than that, but there is still noisy data getting in, and the problem is it causes the UI to be jittery at times.
I would like to smooth this using something like a Circular Buffer. Now I figured the best way to do this would be to store the last 4 float inputs and then effectively calculate the next value based on an average, so say our input was this:10, 15, 20, 25 and 35 is the current input.
15 - 10 = 5
20 - 15 = 5
25 - 20 = 5
Then for the next value, 35 - 25 = 10. 10 + (3 * 5) = 25 / 4 = 6.25...Then adding 6.25 to the previous value resulting in this: 10 15 20 25 31.25 which would appear theoretically smoother. However I'm struggling to work out in my head the best way to implement such a function.
Difference Between Eclipse And JDK?
Feb 27, 2014I'm not sure if that's the right place to ask
But I am a bit confused:
I know that JDK means "Java Development Kit" , but isn't Eclipse the same thing? (so why it's called "IDE"?)
Or maybe Eclipse is a type of JDK?
Or actually JDK and Eclipse are 2 different things
JSF :: Difference Between EventHandler And ActionListener?
Feb 11, 2015What Is the difference between an ActionListener and an EventHandler ?
button.addActionListener(new ActionListener() {
button.setOnAction(new EventHandler<ActionEvent>() {
Difference Between Unused And Unread
Sep 19, 2014exact difference between
1. unread fields
2. unused fileds
in java
Difference Between Abstract And Inheritance
Dec 16, 2014I am new to java i dont understand the difference between the abstract and inheritance i mean we use the abstract class with extends with other class name ,even we do that same in the inheritance pls tell me main difference between abstract and inheritance...
View Replies View RelatedDifference Between Java And JavaScript?
Jul 11, 2014how to program in Javascript, I am wondering what are the advantages and disadvantages OR pros/cons of using JS versus say a language like Java?
View Replies View RelatedHow To Calculate Difference Between Two Dates
Oct 19, 2014I have been tasked with creating an invoice (school assignment). Part of the calculations is creating an interest depending on the amount of days between the current date entered, and invoice date entered (The program prompts the user to enter both the current and invoice dates by asking for the day, month and year).
We are also supposed to set the contructor to a default date of 1/1/1900.. but I don't know how or where to code that.
How to calculate the difference between the CurrentDate and Invoice. I have displayed the dates to the user as follows.
public void displayDate() {
System.out.println("
Today's Date: " + month + "/" + day + "/" + year);
}
public void displayInvDate() {
System.out.println("
Invoice Date: " + invMonth + "/" + invDay + "/" + invYear);
Difference Between LinkedList And ArrayList
Feb 19, 2014I have just begin to understand collections in Java. I read about the differences between LinkedList and ArrayList but have several doubts on it. I have mentioned them below
1) Why retrieving in ArrayList is faster then LinkedList?. Since both have the get method how does performance differ?.
2) How does re-sizing happens internally in ArrayList when a item is added or removed?. How slow this is compared to the pointer re-shuffling in LinkedList when a item is added or removed?.
Difference Between InputStream And InputStreamReader
Jul 11, 2014I read that InputStream is used for byte based reading it reads 1 byte at a time.And InputStreamReader is used for charcter based reading so it reads one charcter at a time so no need to convert this first to int then read it.Here is reading using InputStream.
input=new FileInputStream("D:/input.txt");
int c;
while((c=input.read())!=-1)
{
System.out.print((char)c);
}
and here is reading using InputStreamReader
input=new FileInputStream("D:/input.txt");
reader=new InputStreamReader(input,"UTF-8");
int c;
while((c=reader.read())!=-1)
{
System.out.print((char)c);
}
so what is difference between InputStream and InputStreamReader in both case i have to use a Int and then read it and at the end if I want to print that data I have to cast that with "(char)c".So what is advantage of using InputStreamReader?
Difference Between Protected Or Default
Mar 28, 2015I am new in java. Is there any difference between protected or default when we are talking about one package?
View Replies View RelatedJSP :: Difference Between Jspf And Tags?
Mar 12, 2015I know jspf is a jsp fragment, but can't a tag also serve as a jsp fragment?
View Replies View RelatedDifference Between Application And Applet?
Apr 13, 2014Can explain difference between applet and application?
What are differences in code? How to write application?
What are differences in use? I looked for some answers, but I can't understand what they are talking about.
For example:
Application:
Called as stand-alone application as application can be executed from command prompt
Applet:
Requires some third party tool like a browser to execute
But... While I export applet in exclipse I can use it without any browser, just like application(as I and avarage user knows it).
Ok, I understand difference like "Applets cannot read from or write to hard disk files."
So. What should I use while creating what?
For example, something as simple as windows calc, some 2d simply platformer, some more expanded app, like idk, spotify or media player or whatever?
Since after update 51 of java web applets are nearly useless(as I know, maybe I'm wrong?), what is better?
Can application have GUI or it is only applets thing(stupid question?)?
Where can I find any application tutorial? Everything that I found was for applets. Why?
Difference Between JavaFX And Swing?
Jan 28, 2014I know that oracle has released a statement saying that JavaFX will eventually replace Swing. What is the advantage of JavaFX? The new format, using "stage" instead of JFrame, seemed weird. Why is this change necessary? What benefit do we reap from JavaFX that Swing does not have?
View Replies View RelatedDifference Between Element And Index?
Apr 17, 2014Im working on my homework and it mentioned element for one exercise and an index in another, what is the difference, If Any, Between An Element And An Index?
View Replies View Related