General Java Questions II

It is the same as ==, if it isn t overriden by the object class.

Many classes override the method equals (). In this case this method will check that

content of the object is the same or not, not addresses.

 Q: Why do I get message like  wrong magic number  when I am trying to run

applet? What is magic number?

Answer: The first thing a JVM does when it loads a class is check that the first four

bytes are (in hex) CA FE BA BE. This is the "magic number" and thats why you are

getting that error, you are trying to load a file that isnt a class and so the class loader

in the JVM is throwing out that exception.

Make sure you transfer the class files to site in binary mode, rather than text or ASCII

mode. 

An error from the browser saying "cannot start applet ... bad magic number" usually

means that one of the class files on the server is corrupted.  

Replace your class binary files on the web server; clean up the cache of your

browser, and reload your applet.

Q: In java, I found a lot of methods, which let you enter a line (read (), readLine ()

e.c.t). They all wait until return is pressed, and then start providing you the

information.

Does anyone know if there is a read method available whit the desired behaviour, i.e.

which doesn t wait for return being pressed?

Answer: Java does not provide it, the terminal itself waits until return is pressed

before sending the entered line to Java.

You need to use some platform specific mechanism to change the terminal settings.

Q: Can I pass a function as a parameter in Java? If so, how?

Answer: No, you cannot. But you can pass an object with method and then just use

this method like this:

myFunction (object); // object has method useMyMethod(){ do smth here...}

..

..

somewhere in another place where use this function..

object.useMyMethod();

What is difference capacity() and size() methods for vector?

 What is difference between 

public final int capacity()

Returns the current capacity of this vector.

and 

public final int size()

Returns the number of components in this vector.

Answer: please read this method: ensureCapacity

public final synchronized void ensureCapacity(int minCapacity)

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