java

FastEmbed Java Binding

Native Java binding using JNI for ultra-fast embeddings and vector operations.

Installation

mvn clean install

Usage

import com.fastembed.FastEmbed;

FastEmbed client = new FastEmbed(256);

// Generate embedding
float[] embedding = client.generateEmbedding("Hello, world!");

// Vector operations
float similarity = client.cosineSimilarity(vec1, vec2);
float norm = client.vectorNorm(embedding);
float[] normalized = client.normalizeVector(embedding);

API

See main FastEmbed README for full API documentation.

Building

Prerequisites

• JDK 11+
• Maven 3.6+
• NASM (for assembly)
• C compiler (MSVC on Windows, GCC/Clang on Linux/macOS)

Build Commands

# Build shared library first
cd ../shared && make all

# Compile JNI wrapper
cd ../java
gcc -shared -fPIC -O3 \
    -I"${JAVA_HOME}/include" -I"${JAVA_HOME}/include/linux" \
    -o target/lib/libfastembed.so \
    native/fastembed_jni.c \
    ../shared/build/*.o -lm

# Build Java project
mvn clean install

# Run tests
java -Djava.library.path=target/lib -cp target/fastembed-1.0-SNAPSHOT.jar TestFastEmbedJava

Performance

ONNX Runtime Performance (Nov 2025):

• ONNX embeddings: 22.5-110.7 ms (8-45 emb/s depending on text length)
  • Short text (108 chars): 22.5 ms (45 emb/s) - fastest!
  • Medium text (460 chars): 47.4 ms (21 emb/s)
  • Long text (1574 chars): 110.7 ms (9 emb/s)
• Hash-based embeddings: ~0.01-0.1 ms (~27,000 emb/s average)
• Vector operations: Sub-microsecond latency

See BENCHMARK_RESULTS.md for complete benchmark data.