The best replacement for hsqldb is derby.

The best alternatives to hsqldb are rated as following:
★★★★★  derby
★★★★★  h2
★★★★  sqlite
★  javadb
★  apache derby
  h2 database
  java db

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

Other search terms related to hsqldb and their ratings are:
★★★★★ hibernate
★★★ hibernate example
★ dbunit
★ hibernate tutorial
You have in mind a companion for hsqldb and it is not yet here? Propose!



Google Trends

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hsqldb
derby
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