docs: add README.md for java module

Author: yanghua

java/README.md

@@ -0,0 +1,55 @@
+# Java bindings and SDK for Lance Data Format
+
+> :warning: **Under heavy development**
+
+<div align="center">
+<p align="center">
+
+<img width="257" alt="Lance Logo" src="https://user-images.githubusercontent.com/917119/199353423-d3e202f7-0269-411d-8ff2-e747e419e492.png">
+
+Lance is a new columnar data format for data science and machine learning
+</p></div>
+
+Why you should use Lance
+1. Is order of magnitude faster than parquet for point queries and nested data structures common to DS/ML
+2. Comes with a fast vector index that delivers sub-millisecond nearest neighbors search performance
+3. Is automatically versioned and supports lineage and time-travel for full reproducibility
+4. Integrated with duckdb/pandas/polars already. Easily convert from/to parquet in 2 lines of code
+
+## Quick start
+
+Introduce the Lance SDK for Java Maven dependency(It is recommended to choose the latest version.):
+
+```shell
+<dependency>
+    <groupId>com.lancedb</groupId>
+    <artifactId>lance-core</artifactId>
+    <version>0.18.0</version>
+</dependency>
+```
+
+### Basic I/Os
+
+* create and write a Lance dataset
+* read dataset
+* drop dataset
+
+### Random Access
+
+### Indexing and Searching
+
+### Schema evolution
+
+* add columns
+
+* alter columns
+
+* drop columns
+
+## Integrations
+
+### Spark connector
+
+## Contributing
+
+### Environment(IDE) setup