[Java] How to use RootAllocator in a low memory setting?

When I run this simple code with JVM setting: "-Xmx64m"
```java

package com.snowflake;
import org.apache.arrow.memory.RootAllocator;

public class TestArrow
{
public static void main(String args[]) throws Exception
{
new RootAllocator(Integer.MAX_VALUE);
}
}
```
and got the following error
```java

Picked up JAVA_TOOL_OPTIONS: -Djavax.net.ssl.trustStore=/etc/pki/ca-trust/extracted/java/cacerts
Exception in thread "main" java.lang.ExceptionInInitializerError
at org.apache.arrow.memory.BaseAllocator.createEmpty(BaseAllocator.java:263)
at org.apache.arrow.memory.BaseAllocator.(BaseAllocator.java:89)
at org.apache.arrow.memory.RootAllocator.(RootAllocator.java:34)
at org.apache.arrow.memory.RootAllocator.(RootAllocator.java:30)
at com.snowflake.TestArrow.main(TestArrow.java:13)

Caused by: java.lang.NullPointerException
at io.netty.buffer.PooledByteBufAllocatorL$InnerAllocator.(PooledByteBufAllocatorL.java:145)
at io.netty.buffer.PooledByteBufAllocatorL.(PooledByteBufAllocatorL.java:49)
at org.apache.arrow.memory.AllocationManager.(AllocationManager.java:61) ... 5 more
Process finished with exit code 1
```
So how to use RootAllocator in such low memory case?

**Reporter**: [Andong Zhan](https://issues.apache.org/jira/browse/ARROW-6500)

_{**Note**: *This issue was originally created as [ARROW-6500](https://issues.apache.org/jira/browse/ARROW-6500). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

-Xmx64m を使用する RootAllocator の例から始め、BaseAllocator.createEmpty、RootAllocator、AllocationManager を通した初期化を追跡します。ExceptionInInitializerError を再現し、この低メモリ構成に必要な動作またはガイダンスを判断して、関連する allocator テストで検証します。

索引モデルが issue の本文から書いたものです。