In
`@core/src/main/java/org/opensearch/sql/expression/function/CollectionUDF/MVAppendCore.java`:
- Around line 14-18: Update the JavaDoc for the public method
collectElements(Object... args) in class MVAppendCore: correct the inline tag to
{`@link` MVAppendFunctionImplTest}, add an `@param` tag describing args, add an
`@return` tag that documents the method returns a List of non-null collected
elements or null when all inputs are empty, and add an `@throws` tag (e.g.,
`@throws` NullPointerException) describing that a null args array will cause an
exception; ensure the JavaDoc is placed immediately above the collectElements
method signature.

In
`@core/src/main/java/org/opensearch/sql/expression/function/FunctionResolver.java`:
- Around line 11-12: Replace the invalid Javadoc {`@ref`} tags with {`@link`} in the
interface Javadoc so references to FunctionBuilder and FunctionSignature resolve
correctly; update the doc comment in FunctionResolver (the interface
declaration) to use {`@link` FunctionBuilder} and {`@link` FunctionSignature}
wherever {`@ref` FunctionBuilder} or {`@ref` FunctionSignature} appears.

In
`@core/src/main/java/org/opensearch/sql/expression/function/jsonUDF/JsonExtractAllFunctionImpl.java`:
- Around line 36-40: Update the Javadoc in JsonExtractAllFunctionImpl: replace
the non-standard inline tag {`@ref` JsonExtractAllFunctionImplTest} with the
standard Javadoc tag {`@link` JsonExtractAllFunctionImplTest} so the reference to
the test class is recognized by javadoc; ensure any other occurrences of {`@ref`
...} in the class doc are similarly converted to {`@link` ...}.

In
`@core/src/test/java/org/opensearch/sql/expression/function/CollectionUDF/MapAppendFunctionImplTest.java`:
- Around line 99-107: The test helper assertMapListValues introduces an
unnecessary extracted method; inline its logic back into the tests that call it
and remove the helper. Find the method assertMapListValues in
MapAppendFunctionImplTest, replace each call with the equivalent assertions:
retrieve map.get(key), assert it is a List, cast to List<Object>, assert size
equals expected length and assert each element equals the expectedValues in
order, then delete the assertMapListValues method from the class.

In
`@integ-test/src/test/java/org/opensearch/sql/calcite/remote/CalcitePPLSpathCommandIT.java`:
- Line 27: Update the misleading inline comment that currently reads "Create
test data for string concatenation" to accurately describe the purpose of the
test data for the spath command (e.g., "Create test data for spath command") in
the CalcitePPLSpathCommandIT test so readers know the data is for spath-related
assertions; locate and edit the comment near the test setup in
CalcitePPLSpathCommandIT to make this change.

In
`@integ-test/src/test/java/org/opensearch/sql/calcite/standalone/MapAppendFunctionIT.java`:
- Around line 147-155: The check in assertMapListValue is currently a no-op
(map.containsKey(key)); replace it with an assertion so missing keys fail the
test: in the assertMapListValue method assert that the map contains the provided
key (e.g., using assertTrue or an equivalent assertion helper) before retrieving
value, keeping the rest of the method unchanged (assertMapListValue, map, key,
expectedValues).

In
`@opensearch/src/main/java/org/opensearch/sql/opensearch/request/OpenSearchRequest.java`:
- Around line 57-60: Replace the invalid JavaDoc inline tag {`@ref`
OpenSearchClient.search} in class OpenSearchRequest's method Javadoc with a
proper {`@link`} reference so it renders and passes doclint; change it to {`@link`
OpenSearchClient#search} (or include the full qualified class name if needed) to
correctly link to the search method.