Without default value for source encoding, platform encoding is used, which is bad for build reproducibility. Then setting a default value consistently across every Maven plugin will improve build reproducibility. Proposed default value: ISO-8859-1, which must be supported by every JVM (see java.nio.Charset) and is already the default value for some plugins (the majority of plugins use platform encoding as a default value instead). Note: Using a fixed default value for the encoding instead of the platform encoding can potentially break builds that rely on a platform encoding other than the proposed Latin-1 but did not lock this down in the POM. It is assumed that those builds:

1. are neglectable in number
2. are easy to fix by setting the new property

POM Element for Source File Encoding