minified-java/com.dervarex.minified.java

JavaManager

public final class JavaManager

Resolves, downloads, and caches Java runtimes for Minecraft launches.

This manager can inspect Minecraft version metadata, determine the required Java feature version, and download a matching runtime when the current JVM is too old.

The default runtime cache is placed under a user-specific application directory, but callers may override it with init(Path).

Methods

JavaInstallation currentRuntime()Resolves the current JVM as a Java installation.JavaInstallation ensureExactJavaVersion(int)Ensures that a Java runtime of exactly the given feature version is available.Path ensureJavaExecutable(String)Resolves the Java executable for a Minecraft version, downloading a compatible runtime if the current JVM is too old.Path ensureJavaExecutable(int)Resolves the Java executable for a feature version.JavaInstallation ensureJavaForMinecraftVersion(String)Ensures that a suitable Java runtime is available for a Minecraft version.JavaInstallation ensureJavaVersion(int)Ensures that a suitable Java runtime is available for the given feature version.Path getBaseDir()int getRequiredJavaVersion(JsonValue)Reads the required Java major version from a Minecraft version JSON document.int getRequiredJavaVersion(JsonFile)Reads the required Java major version from a Minecraft version JSON document.int getRequiredJavaVersion(String)Resolves the required Java version for the given Minecraft version id.int getRequiredJavaVersion(Path)Resolves the required Java version for the given Minecraft version id from a local cache file.String getVersionJsonUrl(String)Resolves the version JSON URL for a Minecraft version id.void init(Path, EventBus)Configures the root directory used for managed Java runtimes.void init(Path)

currentRuntime()

staticSource

public static JavaInstallation currentRuntime()

Resolves the current JVM as a Java installation.

Returns
`JavaInstallation`		The current runtime information

ensureExactJavaVersion(int)

staticexperimentalSource

public static JavaInstallation ensureExactJavaVersion(int requiredMajorVersion) throws HttpException, IOException

Ensures that a Java runtime of exactly the given feature version is available. Unlike ensureJavaVersion(int), a newer current JVM is not accepted, which is needed for Minecraft mod loaders relying on the Java 8 class loader May download and extract a runtime (network and disk I/O)

Parameters
`requiredMajorVersion`	`int`	The required Java feature version
Returns
`JavaInstallation`		The current JVM if it has exactly the required feature version, otherwise a managed Java installation
Throws
`HttpException`		If the runtime manifest request fails
`IOException`		If a runtime download or extraction fails

ensureJavaExecutable(String)

staticSource

public static Path ensureJavaExecutable(String minecraftVersion) throws HttpException, IOException

Resolves the Java executable for a Minecraft version, downloading a compatible runtime if the current JVM is too old.

Parameters
`minecraftVersion`	`String`	The Minecraft version id
Returns
`Path`		The Java executable to use for launching Minecraft
Throws
`HttpException`		If a manifest request fails
`IOException`		If a runtime download or extraction fails

ensureJavaExecutable(int)

staticSource

public static Path ensureJavaExecutable(int requiredMajorVersion) throws HttpException, IOException

Resolves the Java executable for a feature version.

Parameters
`requiredMajorVersion`	`int`	The required Java feature version
Returns
`Path`		The Java executable to use for launching Minecraft
Throws
`HttpException`		If a runtime manifest request fails
`IOException`		If a runtime download or extraction fails

ensureJavaForMinecraftVersion(String)

staticSource

public static JavaInstallation ensureJavaForMinecraftVersion(String minecraftVersion) throws HttpException, IOException

Ensures that a suitable Java runtime is available for a Minecraft version.

Parameters
`minecraftVersion`	`String`	The Minecraft version id, such as `1.21.4`
Returns
`JavaInstallation`		The current JVM if it matches the required feature version, otherwise a managed Java installation
Throws
`HttpException`		If a manifest request fails
`IOException`		If a runtime download or extraction fails

ensureJavaVersion(int)

staticSource

public static JavaInstallation ensureJavaVersion(int requiredMajorVersion) throws HttpException, IOException

Ensures that a suitable Java runtime is available for the given feature version.

Parameters
`requiredMajorVersion`	`int`	The required Java feature version
Returns
`JavaInstallation`		The current JVM if it matches the required feature version, otherwise a managed Java installation
Throws
`HttpException`		If the runtime manifest request fails
`IOException`		If a runtime download or extraction fails

getBaseDir()

staticSource

public static Path getBaseDir()

Returns
`Path`		The configured root directory used for managed Java runtimes

getRequiredJavaVersion(JsonValue)

staticSource

public static int getRequiredJavaVersion(JsonValue versionJson)

Reads the required Java major version from a Minecraft version JSON document.

Parameters
`versionJson`	`JsonValue`	A parsed Minecraft version JSON
Returns
`int`		The required Java major version, or `-1` if the document does not contain one

getRequiredJavaVersion(JsonFile)

staticSource

public static int getRequiredJavaVersion(JsonFile versionJson)

Reads the required Java major version from a Minecraft version JSON document.

Parameters
`versionJson`	`JsonFile`	A parsed Minecraft version JSON file
Returns
`int`		The required Java major version, or `-1` if the document does not contain one

getRequiredJavaVersion(String)

staticSource

public static int getRequiredJavaVersion(String minecraftVersion) throws HttpException, IOException

Resolves the required Java version for the given Minecraft version id.

Parameters
`minecraftVersion`	`String`	The Minecraft version id, such as `1.21.4`
Returns
`int`		The required Java major version, or `-1` if it could not be resolved
Throws
`HttpException`		If a manifest request fails
`IOException`		If the version JSON cannot be read

getRequiredJavaVersion(Path)

staticSource

public static int getRequiredJavaVersion(Path versionJsonPath) throws IOException

Resolves the required Java version for the given Minecraft version id from a local cache file.

Parameters
`versionJsonPath`	`Path`	The cached Minecraft version JSON path
Returns
`int`		The required Java major version, or `-1` if it could not be resolved
Throws
`IOException`		If the file cannot be read

getVersionJsonUrl(String)

staticSource

public static String getVersionJsonUrl(String minecraftVersion) throws HttpException, IOException

Resolves the version JSON URL for a Minecraft version id.

Parameters
`minecraftVersion`	`String`	The Minecraft version id
Returns
`String`		The Mojang metadata URL, or `null` if the version was not found
Throws
`HttpException`		If the version manifest request fails
`IOException`		If the manifest cannot be read

init(Path, EventBus)

staticSource

public static void init(Path baseDir, EventBus eventBus)

Configures the root directory used for managed Java runtimes.

Parameters
`baseDir`	`Path`	The directory where managed runtimes will be stored
`eventBus`	`EventBus`	The EventBus Events will be pushed to

init(Path)

staticSource

public static void init(Path baseDir)

Parameters
`baseDir`	`Path`