B + Tree on disk in Java

Question

Does anyone know where to find the B + Tree on disk? I went through google back and forth and, unfortunately, I could not find anything reasonable. Other threads suggested, perhaps, to take the tree from sqlite, sqljet or bdb, but these trees are nested in the entire database, and you cannot just simply filter the B + tree. I'm really only looking for a B + Tree drive ... without any fancy stuff.

Answer 1

There is a Java persistence mechanism based on GDBM: MapDB

Answer 2

In the past, I implemented disk B + -tree. https://github.com/myui/xbird/blob/master/xbird-open/main/src/java/xbird/storage/index/BIndexFile.java

Find usage at https://github.com/myui/xbird/blob/master/xbird-open/main/test/java/xbird/storage/index/BIndexMultiValueFileTest.java

Answer 3

If you need it for real use, and not for educational purposes (studying the data structure of B + Tree, etc.), LMDBJava is probably the best solution available in Java now. It's not B + Tree for sure, but a sorted keystore, so it's pretty much the same as B + Tree.