Structs In Java - Can Put Class Inside A Class?
Mar 17, 2014
I will give an example below of what I am talking about. in C++ I know I would need a copy constructor because I would be pointing blindly in the heap if I deleted a object in the struct.
We have a Class/struct animal and three animals in that class/struct, a dog, a cat and a cow. Each animal has a baby and then I will give the animal a name in main. But if I delete one of the dogs puppies because I sold him wouldn't I being pointing off in the heap and have a leak?
Also since Java doesn't have structs can I put a class inside a class?
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Apr 22, 2015
How to create object for "class B" and call the "function_B" from other different class D where class D has no connection with class A? Here is my program.
public class A(){
void print(){}
}
class B{
void function_B(){}
}
class C{
void function_C(){}
}
Here, A, B, C are in the same package. But class D is in different package.
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Jun 21, 2013
Can we write java class or code inside Oracle Stored procedure.
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Feb 26, 2015
try {
File configFile= new File("C: Documents and SettingsstudentMy DocumentsNetBeansProjectsCDASsrcconfig.xml ");
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(fXmlFile);
doc.getDocumentElement().normalize();
NodeList nList = doc.getElementsByTagName("config");
[Code] .....
This code is working properly but i have use path like this
File configFile= new File("srcconfig.xml");
Instead of system directory path i have to use path inside of project but i am getting an error-cannot find the specified file...
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Oct 28, 2014
I have to modify my ContainerImpl.java inside a .jar file. My modification is in here: [URL] but I do not know how can I modify it
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Apr 13, 2014
Ok say you have
public class MyClass {
private int x = 5;
Object myObject = new Object();
public MyClass(){
}
}
When would the myObject be created? Before or after the constructor? And does this mean you can't pass
this into the parameters of that object?
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Jun 22, 2014
I am not able to understand how we are able to create an object of static inner class defined inside an interface .
interface outer {
class inner {
void disp() {
System.out.println("inside disp");
[Code] ....
output:
inside disp
How am i able to create a new object for static class?
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Feb 15, 2014
Can a class be defined inside an Interface .
interface Inter{
class x{
public static void main(String[] args){
System.out.println("Hello World!");
}
}
}
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May 8, 2013
I have a doubt regarding to java.
Can we declare a class inside an interface?
Ans :yes
But what will be the situation?
I am not getting why it is required...........
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Jul 8, 2015
What this interface inside that abstract class does. Looking for some examples to how can i use it ....
public abstract class Expression {
public abstract String toString();
public abstract SimpleExpression evaluate();
public void show() {
System.out.println(this + " = " + evaluate());
[Code] ....
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Feb 17, 2014
I am puzzled by a note in the book I am reading (by Mala Gupta). Page 55 says "All java components you've heard of can be defined within a java class: import and package statements, variables.....". But the online oracle doc (tutorial) clearly says the following 2 statments:
"If present, package statement must be the very first line in a file"
"To import a specific member into the current file, put an import statement at the beginning of the file before any type definitions but after the package statement, if there is one. " (Here).
So, how can import and package be present inside a class ? (This seems to go against the 2 statements from oracle online tutorial).
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Mar 7, 2015
I'm trying to access class file which is inside the package and package is inside the jar file but I can't access that class file inside my source file . All files are on desktop .
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Mar 1, 2015
Does child class gets a copy of the methods and variables of parent class?
public class test1 {
public static void main(String a[]) {
Child c = new Child();
c.print();
[Code] ....
why is the output 1?
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Jul 14, 2014
i want to write a class in such a way that i should get the current execution time of another class which is running. I searched in net but it shows only how to calculate the time duration of the current class which is running. But as per my way, i need the execution time of one class from another class. How to do this ?
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Jan 21, 2014
I saw an example where an (inner)class is declared inside the main method, this is correct or not and why/when it's reasonable to use?so smth like this
public class myClass()
{
public static void myMethod(myInnerClass obj)
{
if (obj.method())
[code]....
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Mar 12, 2015
How do I create an instance of a class in a method?
I am a bit rusty whenever I think of instances. I always think of main method and objects when I see instance which gets me confused on what to do when I am not in a main method. The example:
I have a abstract class, School, and inside School I have some methods that must preform some action on an instance. For example, there is a move() method that must move the instance of School. Another method named, personOld(), which returns whether or not an instance of School surpassed some determined age.
How do I do this and create this instance?
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Aug 9, 2014
this code won't compile because selected row must be declared as final because of it being defined outside the window listener. Is their anyway around this? If I make it final the first time that the variable is called it keeps it starting value until the GUI is closed.
butEdit.addActionListener (new ActionListener () {
@Override
public void actionPerformed (java.awt.event.ActionEvent evt) {
int selectedRow = table.getSelectedRow ();
final String [] values = custTableModel.getRowValues (selectedRow);
[code]....
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Feb 22, 2014
I know that the simple deployment using only applet tags inside HTML causes severe security restriction for the applet on the client side. but can this simple HTML file contains .jar files inside the applet tags instead of .class files.
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Apr 3, 2014
Created a java.sql.connection object. Refering those obj inside public void run() { } If i declare as final inside a method, i can't refer those outside method due to scope. Cannot refer to a non-final variable dbConnObj inside an inner class defined in a different method...
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May 13, 2014
I have an application which is doing a fine job of placing the total hours on the interface.
Where I am breaking down is that I am unable to split the string into two distinct groups: hours and minutes
private HtmlElement createTravelTimeRow(ShowSet showSet) {
HtmlElement tr = new HtmlElement(ROW_OPEN, ROW_CLOSE);
HtmlElement td = new HtmlElement(CELL_OPEN, CELL_CLOSE);
[Code].....
I came across something which showed how to split the String but I am still very unsure how to do this.
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Sep 13, 2014
I am working on a calculator for Android.To make sure the application I am developing works with multiple operations (in the correct order) I decided to use ANTLR as part of my Java coding of the calculator. So in a separate file (.g4 file), I must declare the format of the expression.
E.G.
grammar Expr;
prog:(expr NEWLINE)* ;
expr:expr ('*'|'/') expr
|expr ('+'|'-') expr
|INT
|'(' expr ')'
;
NEWLINE : [
]+ ;
INT : [0-9]+ ;
After which I need to include the ANTLR class library in my Java Class. Then I believe I need to call a set of functions such as createLexerInterpreter and createParserInterpreter, but I am not sure. I will be having an algorithm string that will need to be parsed, such as " 3+4*5+8*9+(5/6) ".
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Mar 5, 2015
How do you declare methods for a class within the class whilst objects of the class are declared else where?
Say for instance, I have a main class Wall, and another class called Clock, and because they are both GUI based, I want to put a Clock on the Wall, so I have declared an instance object of Clock in the Wall class (Wall extends JFrame, and Clock extends JPanel).
I now want to have methods such as setClock, resetClock in the Clock class, but im having trouble in being able to refer to the Clock object thats been declared in the Wall class.
Is this possible? Or am I trying to do something thats not possible? Or maybe I've missed something really obvious?
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Feb 18, 2014
Class UserAssessBean{
private String username;
private int userid;
private ArrayList<ModuleBean> module;
--{get/set}--
[Code] ....
How can i access the getters/setters of module bean, when it was returned as array list in UserAssessBean?
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May 28, 2014
Regarding the lifecycle of servlet , in headfirst servlet i can find :
You normally will NOT override the service() method, so the one from HttpServlet will run. The service() method figures out which HTTP method (GET, POST, etc.) is in the request, and invokes the matching doGet() or doPost() method. The doGet() and doPost() inside HttpServlet don’t do anything, so you have to override one or both. This thread dies (or is put back in a Container-managed pool) when service() completes.
How can I call the doGet method of the subclass from the superclass. i am not getting this .
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Apr 14, 2015
I have a quick polymorphism question. I have a parent class and a sub class that extends the parent class. I then declare an array of parent class but instantiate an index to the sub class using polymorphism. Do I have to have all the same methods in the child class that I do in the parent class? Here is an example of what I mean.
public class ParentClass
{
public ParentClass(....){ }
public String doSomething(){ }
}
public class ChildClass extends ParentClass
{
public ChildClass(....)
[Code] ....
Is polymorphism similar to interfaces where the child class needs all the same methods?
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Feb 4, 2015
I want to know is there any way we can call parent class method using child class object without using super keyword in class B in the following program like we can do in c++ by using scoop resolution operator
class A{
public void hello(){
System.out.println("hello");
}
}
class B extends A{
public void hello(){
//super.hello();
System.out.println("hello1");
[code]....
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