JTable is a Swing component in Java that displays data in a tabular format. Often, you may want to sort the data in a JTable based on one or more columns. Here are six techniques for sorting a JTable in Java 6:

1. Using the default row sorter: JTable provides a default implementation of the RowSorter interface that can be used for sorting. You can access the row sorter by calling the getRowSorter() method on the JTable instance, and then call its setSortKeys() method to specify the column(s) to sort by.

2. Implementing a custom row sorter: You can implement your own RowSorter to perform more complex sorting operations, such as sorting by multiple columns or sorting on data that is not displayed in the table. To use your custom sorter, you can call the setRowSorter() method on the JTable instance.

3. Using a Comparator: You can use a Comparator to define how the data in a particular column should be sorted. To do this, you need to create a RowSorter.SortKey instance that specifies the column index and the Comparator to use for that column.

4. Using a TableSorter: You can use a TableSorter class to add sorting functionality to a JTable. The TableSorter class wraps a TableModel and provides methods to sort the data based on one or more columns. You can then use the sorted data in the TableSorter to populate the JTable.

5. Using a TableRowSorter: Java 6 introduced the TableRowSorter class, which provides a more efficient and flexible way to sort data in a JTable. TableRowSorter is also more customizable than the default RowSorter implementation. You can create a TableRowSorter instance and then set it as the row sorter for the JTable.

6. Using a ComparatorChain: If you need to sort by multiple columns, you can use the ComparatorChain class to create a chain of Comparator instances. The ComparatorChain class applies each Comparator in the chain until it finds a column where the values differ, and then returns the result.

These are some of the techniques that you can use to sort a JTable in Java 6. Which one you choose will depend on the complexity of your sorting needs and the level of customization you require.