JBang¶

A JBang script keeps its first line and its directives, such as //DEPS, exactly as written: no space after the slashes and no wrapping.

Default rules

/// usr/bin/env jbang "$0" "$@" ; exit $?
// JAVA 21+
// DEPS info.picocli:picocli:4.7.6

import picocli.CommandLine;

With the JBang rule

///usr/bin/env jbang "$0" "$@" ; exit $?
//JAVA 21+
//DEPS info.picocli:picocli:4.7.6

import picocli.CommandLine;

JBang reads a directive only when its name comes right after the slashes. Under the default rules it drops the Java version and the dependency, so the script no longer compiles, and a shell that runs the file takes /// for the command and fails.

When it applies¶

Only in the comments at the top of the file, before the first line of code, which is where JBang's documentation puts directives. After the package declaration, an import or a class, the same text is an ordinary comment and gets its space.

Two kinds of line stay as written there:

A directive: one of JBang's names right after the slashes, followed by a space or the end of the line. The names are CDS, COMPILE_OPTIONS, DEPS, DESCRIPTION, DOCS, FILES, GAV, GROOVY, JAVA, JAVAAGENT, JAVAC_OPTIONS, JAVA_OPTIONS, KOTLIN, MAIN, MANIFEST, MODULE, NATIVE_OPTIONS, NOINTEGRATIONS, PREVIEW, REPOS, RUNTIME_OPTIONS and SOURCES. A name behind an integration's prefix, such as Quarkus's //Q:CONFIG, counts as well.
The first line of the file, when its first word is a path, as in ///usr/bin/env jbang or //usr/bin/env jbang.

Other comments there, such as //deps or //TODO, get their space as before.

A script that was formatted before 2.98.0.5, or with palantir-java-format or google-java-format, already has the spaces, and the formatter does not take them out. Remove them by hand once.

The rule is our own and came in 2.98.0.5 (#24). In google-java-format the same request is still open as #1217.