Java Collections – Sets

There are two java data types I’m going to cover, hashsets and treesets. 


A hash table is another type array.  A hash table consists of keys and values.  Each key must be unique and  they are used to reference the data stored in the value field.  Here is a sample snippet for a hash table.

public class HashSet
private HashSet hash;

// Builds a hash set from a string array
public HashSet(String[] arr){
this.hash = new HashSet();

for(String str: arr)

Binary Trees

Trees are implemented in a similar fashion as hash sets.  Using TreeSet will organize your data into a binary tree.

public class TreeSet{
private TreeSet tree;

//Builds binary tree from string array
public TreeSet(String[] arr){

this.tree = TreeSet();
for (String str: arr)

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