Java Bindings for llama.cpp

Inference of Meta's LLaMA model (and others) in pure C/C++.

You are welcome to contribute

1. Quick Start
   1.1 No Setup required
   1.2 Setup required
2. Documentation
   2.1 Example
   2.2 Inference
   2.3 Infilling
3. Android

Note

Now with support for Llama 3, Phi-3, and flash attention

Quick Start

Access this library via Maven:

<dependency>
    <groupId>de.kherud</groupId>
    <artifactId>llama</artifactId>
    <version>3.3.0</version>
</dependency>

There are multiple examples.

No Setup required

We support CPU inference for the following platforms out of the box:

• Linux x86-64, aarch64
• MacOS x86-64, aarch64 (M-series)
• Windows x86-64, x64, arm (32 bit)

If any of these match your platform, you can include the Maven dependency and get started.

Setup required

If none of the above listed platforms matches yours, currently you have to compile the library yourself (also if you want GPU acceleration).

This consists of two steps: 1) Compiling the libraries and 2) putting them in the right location.

Library Compilation

First, have a look at llama.cpp to know which build arguments to use (e.g. for CUDA support). Any build option of llama.cpp works equivalently for this project. You then have to run the following commands in the directory of this repository (java-llama.cpp):

mvn compile  # don't forget this line
cmake -B build # add any other arguments for your backend, e.g. -DGGML_CUDA=ON
cmake --build build --config Release

Tip

Use -DGGML_CURL=ON to download models via Java code using ModelParameters#setModelUrl(String).

All compiled libraries will be put in a resources directory matching your platform, which will appear in the cmake output. For example something like:

--  Installing files to /java-llama.cpp/src/main/resources/de/kherud/llama/Linux/x86_64

Library Location

This project has to load three shared libraries:

• ggml
• llama
• jllama

Note, that the file names vary between operating systems, e.g., ggml.dll on Windows, libggml.so on Linux, and libggml.dylib on macOS.

The application will search in the following order in the following locations:

• In de.kherud.llama.lib.path: Use this option if you want a custom location for your shared libraries, i.e., set VM option -Dde.kherud.llama.lib.path=/path/to/directory.
• In java.library.path: These are predefined locations for each OS, e.g., /usr/java/packages/lib:/usr/lib64:/lib64:/lib:/usr/lib on Linux. You can find out the locations using System.out.println(System.getProperty("java.library.path")). Use this option if you want to install the shared libraries as system libraries.
• From the JAR: If any of the libraries weren't found yet, the application will try to use a prebuilt shared library. This of course only works for the supported platforms .

Not all libraries have to be in the same location. For example, if you already have a llama.cpp and ggml version you can install them as a system library and rely on the jllama library from the JAR. This way, you don't have to compile anything.

Documentation

Example

This is a short example on how to use this library:

public class Example {

    public static void main(String... args) throws IOException {
        ModelParameters modelParams = new ModelParameters()
                .setModelFilePath("/path/to/model.gguf")
                .setNGpuLayers(43);

        String system = "This is a conversation between User and Llama, a friendly chatbot.\n" +
                "Llama is helpful, kind, honest, good at writing, and never fails to answer any " +
                "requests immediately and with precision.\n";
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in, StandardCharsets.UTF_8));
        try (LlamaModel model = new LlamaModel(modelParams)) {
            System.out.print(system);
            String prompt = system;
            while (true) {
                prompt += "\nUser: ";
                System.out.print("\nUser: ");
                String input = reader.readLine();
                prompt += input;
                System.out.print("Llama: ");
                prompt += "\nLlama: ";
                InferenceParameters inferParams = new InferenceParameters(prompt)
                        .setTemperature(0.7f)
                        .setPenalizeNl(true)
                        .setMirostat(InferenceParameters.MiroStat.V2)
                        .setAntiPrompt("\n");
                for (LlamaOutput output : model.generate(inferParams)) {
                    System.out.print(output);
                    prompt += output;
                }
            }
        }
    }
}

Also have a look at the other examples.

Inference

There are multiple inference tasks. In general, LlamaModel is stateless, i.e., you have to append the output of the model to your prompt in order to extend the context. If there is repeated content, however, the library will internally cache this, to improve performance.

ModelParameters modelParams = new ModelParameters().setModelFilePath("/path/to/model.gguf");
InferenceParameters inferParams = new InferenceParameters("Tell me a joke.");
try (LlamaModel model = new LlamaModel(modelParams)) {
    // Stream a response and access more information about each output.
    for (LlamaOutput output : model.generate(inferParams)) {
        System.out.print(output);
    }
    // Calculate a whole response before returning it.
    String response = model.complete(inferParams);
    // Returns the hidden representation of the context + prompt.
    float[] embedding = model.embed("Embed this");
}

Note

Since llama.cpp allocates memory that can't be garbage collected by the JVM, LlamaModel is implemented as an AutoClosable. If you use the objects with try-with blocks like the examples, the memory will be automatically freed when the model is no longer needed. This isn't strictly required, but avoids memory leaks if you use different models throughout the lifecycle of your application.

Infilling

You can simply set InferenceParameters#setInputPrefix(String) and InferenceParameters#setInputSuffix(String).

Model/Inference Configuration

There are two sets of parameters you can configure, ModelParameters and InferenceParameters. Both provide builder classes to ease configuration. ModelParameters are once needed for loading a model, InferenceParameters are needed for every inference task. All non-specified options have sensible defaults.

ModelParameters modelParams = new ModelParameters()
        .setModelFilePath("/path/to/model.gguf")
        .setLoraAdapter("/path/to/lora/adapter")
        .setLoraBase("/path/to/lora/base");
String grammar = """
		root  ::= (expr "=" term "\\n")+
		expr  ::= term ([-+*/] term)*
		term  ::= [0-9]""";
InferenceParameters inferParams = new InferenceParameters("")
        .setGrammar(grammar)
        .setTemperature(0.8);
try (LlamaModel model = new LlamaModel(modelParams)) {
    model.generate(inferParams);
}

Logging

Per default, logs are written to stdout. This can be intercepted via the static method LlamaModel.setLogger(LogFormat, BiConsumer<LogLevel, String>). There is text- and JSON-based logging. The default is JSON. Note, that text-based logging will include additional output of the GGML backend, while JSON-based logging only provides request logs (while still writing GGML messages to stdout). To only change the log format while still writing to stdout, null can be passed for the callback. Logging can be disabled by passing an empty callback.

// Re-direct log messages however you like (e.g. to a logging library)
LlamaModel.setLogger(LogFormat.TEXT, (level, message) -> System.out.println(level.name() + ": " + message));
// Log to stdout, but change the format
LlamaModel.setLogger(LogFormat.TEXT, null);
// Disable logging by passing a no-op
LlamaModel.setLogger(null, (level, message) -> {});

Importing in Android

You can use this library in Android project.

1. Add java-llama.cpp as a submodule in your android app project directory

git submodule add https://github.com/kherud/java-llama.cpp 

2. Declare the library as a source in your build.gradle

android {
    val jllamaLib = file("java-llama.cpp")

    // Execute "mvn compile" if folder target/ doesn't exist at ./java-llama.cpp/
    if (!file("$jllamaLib/target").exists()) {
        exec {
            commandLine = listOf("mvn", "compile")
            workingDir = file("java-llama.cpp/")
        }
    }

    ...
    defaultConfig {
	...
        externalNativeBuild {
            cmake {
		// Add an flags if needed
                cppFlags += ""
                arguments += ""
            }
        }
    }

    // Declare c++ sources
    externalNativeBuild {
        cmake {
            path = file("$jllamaLib/CMakeLists.txt")
            version = "3.22.1"
        }
    }

    // Declare java sources
    sourceSets {
        named("main") {
            // Add source directory for java-llama.cpp
            java.srcDir("$jllamaLib/src/main/java")
        }
    }
}

3. Exclude de.kherud.llama in proguard-rules.pro

keep class de.kherud.llama.** { *; }