commons

Apache Commons Lang, a package of Java utility classes for the classes that are in java.lang's hierarchy, or are considered to be so standard as to justify existence in java.lang.

The Apache Commons Collections package contains types that extend and augment the Java Collections Framework.

Apache Commons Compress software defines an API for working with compression and archive formats. These include: bzip2, gzip, pack200, lzma, xz, Snappy, traditional Unix Compress, DEFLATE, DEFLATE64, LZ4, Brotli, Zstandard and ar, cpio, jar, tar, zip, dump, 7z, arj.

The Apache Commons Math project is a library of lightweight, self-contained mathematics and statistics components addressing the most common practical problems not immediately available in the Java programming language or commons-lang.

Commons-IO contains utility classes, stream implementations, file filters, and endian classes.

The Apache Commons Object Pooling Library.

Apache Commons Text is a library focused on algorithms working on strings.

Tools to assist in the reading of configuration/preferences files in various formats

Apache Commons Exec is a library to reliably execute external processes from within the JVM.

The Apache Commons CSV library provides a simple interface for reading and writing CSV files of various types.