Enable Ant in Eclipse

1 Show Ant View. Window → Show View → Other…
2. Under Ant folder you should see ‘Ant’, select it and click OK.

Add an association between build.xml and the Ant editor

1. Open “File Associations” preferences. Window → Preferences → General → Editors → File Associations

2. Add build.xml in File Types

3. Type build.xml in “Add File Type” Dialog and click OK

4. In Associated editors select Ant Editor and click Default