How can I program linked lists if Java doesn't have pointers?

Ans : Of all the misconceptions about Java, this is the most egregious. Far from not having pointers, in Java, object-oriented programming is conducted exclusively with pointers. In other words, objects are only ever accessed through pointers, never directly. The pointers are termed "references" and they are automatically dereferenced for you.

Java does not have pointer arithmetic or untyped casting. By removing the ability for programmers to create and modify pointers in arbitrary ways, Java makes memory management more reliable, while still allowing dynamic data structures. Also note that Java has NullPointerException, not NullReferenceException.

A linked list class in Java might start like this:

public class LinkedList {
public LinkedList head;
public LinkedList next;
public Object data;
public LinkedList advanceToNext(LinkedList current) { ...
}

Another choice for a linked list structure is to use the built-in class java.util.Vector which accepts and stores arbitrary amounts of Object data (as a linked list does), and retrieves it by index number on demand (as an array does). It grows automatically as needed to accommodate more elements. Insertion at the front of a Vector is a slow operation compared with insertion in a linked list, but retrieval is fast. Which is more important in the application you have!.

Note: java.util.Vector is thread safety.. so it is slow. If you are not worried about thead safety, it is better to user java.util.List.

Does Java have pointers?

Ans : No, no, a thousand times no. Java does not have pointers, no way. Java does have references. A reference is an abstract identifier for an object. It is not a pointer. A reference tags a particular object with a name in the Java virtual machine so that the programmer may refer to it. How exactly the virtual machine implements references at the level of machine code is VM-dependent and completely hidden from the programmer in any case. Most VMs including Sun's use handles, not pointers. A handle is a pointer to a pointer. At the level of machine code in the CPU a reference is an address in memory where the address of the object is stored. This way the objects can be moved around in memory and only the master pointer needs to be updated rather than all references to the object. This is completely hidden from the Java programmer, though. Only the implementer of the virtual machine needs to worry about it. Indeed, this is not the only way references can be implemented. Microsoft's VM actually does use pointers rather than handles. Other schemes are possible.

What are the ways to learn Java?

Ans : Following steps makes easy to learn java.

1. Start with a java tutorial provided by sun.

2. And get basic book that covers all language fundamental, U can get several java book online too..( See our Related Doc or Related books for more info.)

3. You can also get a compile from sun site to write and test sample programs.