The tHash (tHashInput and tHashOutput) components are very usefull to use in your jobs. Talend does not automatically enable these components for use in jobs.
To enable the tHashInput and tHashOutput components perform the following instructions:
1: On the main menu navigate to File –> Edit Project properties
2: Select Designer –> Palette Settings
3: Go to technical –> select tHashInput/tHashOutput and press the right arrow.