feat: Add Java Module (#314)

Implements a Java module which shows basic Java information when inside a Java project.

docs/config/README.md

@@ -93,6 +93,7 @@ prompt_order = [
     "rust",
     "python",
     "golang",
+    "java",
     "nix_shell",
     "cmd_duration",
     "line_break",
@@ -493,6 +494,31 @@ impure_msg = "impure shell"
 pure_msg = "pure shell"
 ```
 
+## Java
+
+The `java` module shows the currently installed version of Java.
+The module will be shown if any of the following conditions are met:
+
+- The current directory contains a `pom.xml` or `build.gradle` file
+- The current directory contains a file with the `.java`, `.class` or `.jar` extension
+
+### Options
+
+| Variable   | Default        | Description                                              |
+| ---------- | -------------- | -------------------------------------------------------- |
+| `symbol`   | `"☕ "`         | The symbol used before displaying the version of Java.  |
+| `style`    | `"dimmed red"` | The style for the module.                               |
+| `disabled` | `false`        | Disables the `java` module.                              |
+
+### Example
+
+```toml
+# ~/.config/starship.toml
+
+[java]
+symbol = "🌟 "
+```
+
 
 ## NodeJS