The best replacement for swt is swing.

The best alternatives to swt are rated as following:
★★★★★  swing
★★★  awt
★★★  jface
★★  rcp
★★  gwt
★★  qt
★★  javafx
★  javafx 2
★  saml
  fpt

Your alternative for swt is not listed? Suggest!
Speaking about swt, one probably shouldn't forget about eclipse.

Other search terms related to swt and their ratings are:
★★★★★ eclipse
You have in mind a companion for swt and it is not yet here? Propose!



Google Trends

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swt
swing
awt