[JAVA] Update JDBC docs

[chernser]

Summary

• Updates type mapping for V2
• Adds explanation of V2 array base type mapping
• Updates migration difference.

Closes: ClickHouse/clickhouse-java#2746

Checklist

• Delete items not relevant to your PR
• URL changes should add a redirect to the old URL via https://github.com/ClickHouse/clickhouse-docs/blob/main/vercel.json
• If adding a new integration page, also add an entry to the integrations list here: https://github.com/ClickHouse/clickhouse-docs/blob/main/docs/integrations/index.mdx

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Note

Low Risk
Documentation-only changes to jdbc.mdx; no runtime, security, or API code is modified.

Overview
Updates the Java JDBC integration docs to match JDBC V2 type metadata and migration guidance.

Type mapping tables now list standard JDBC type codes (e.g. TINYINT (-6), VARCHAR (12)) alongside type names. Scalar mappings are corrected for V2: wide integers and UInt64 use NUMERIC instead of OTHER; unsigned integers map to signed JDBC numeric types with standard Java boxed types; Float32 is FLOAT not REAL; Enum8/Enum16 are VARCHAR.

A new Array element type metadata section documents Array.getBaseTypeName() / getBaseType() for V2, including nested Nullable, LowCardinality, Tuple, UUID, and multi-dimensional arrays, and notes that V2 keeps full ClickHouse type signatures where V1 strips them.

The V1 vs V2 migration tables are aligned with the same JDBC/Java class changes (unsigned types, NUMERIC, FLOAT, and V1 DateTime/DateTime64 as TIMESTAMP_WITH_TIMEZONE with OffsetDateTime).

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[vercel]

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Project	Deployment	Actions	Updated (UTC)
clickhouse-docs	Ready	Preview, Comment	May 28, 2026 12:38am

4 Skipped Deployments

Project	Deployment	Actions	Updated (UTC)
clickhouse-docs-jp	Ignored		May 28, 2026 12:38am
clickhouse-docs-ko	Ignored		May 28, 2026 12:38am
clickhouse-docs-ru	Ignored		May 28, 2026 12:38am
clickhouse-docs-zh	Ignored		May 28, 2026 12:38am

[mintlify]

Docs PR opened: ClickHouse/mintlify-docs-dev#89

Updated the Java JDBC docs with V2 type codes, revised type mappings, and a new Array element metadata section.

Once this PR is merged, we'll do a second pass to capture any additional changes and update the docs PR.

[mshustov]

is it precision or a constant? the column legend doesn't tell much

[mshustov]

I'd vote to move Example to a separate column since it's hard to read (at least in markdown)