[Java][Native] Fix request compression

[inemtsev]

During testing of the newly added Gzip feature for Java+native template, we discovered that request was missing the gzip header in the stream because it was being cleared by the buffer.reset() method. This PR:

• Fixes the missing gzip header by applying it after the reset.
• Increase the size of decompression buffer to 8KB from 512bytes default. 512 bytes is tiny, competing Http clients like OkHttp and Apache use 8KB by default.

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---

Summary by cubic

Fixes gzip request compression in the Java native client so the gzip header is preserved. Also enables streaming gzip for requests and uses an 8KB buffer for response decompression.

• Bug Fixes

  • Initialize gzip after buffer.reset to keep the gzip header in the stream.

• New Features

  • Stream gzip request bodies via ApiClient.gzipRequestBody and set Content-Encoding/Accept-Encoding headers; enabled via useGzipFeature in config.
  • Use an 8KB GZIPInputStream buffer for response decompression.

^{Written for commit 0136e92. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 4 files

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="samples/client/petstore/java/native-useGzipFeature/src/main/java/org/openapitools/client/ApiClient.java">

<violation number="1" location="samples/client/petstore/java/native-useGzipFeature/src/main/java/org/openapitools/client/ApiClient.java:564">
P2: read(byte[],off,len) violates InputStream contract by returning -1 on zero-length reads at EOF instead of 0</violation>
</file>

---

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[cubic-dev-ai]

P2: read(byte[],off,len) violates InputStream contract by returning -1 on zero-length reads at EOF instead of 0

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At samples/client/petstore/java/native-useGzipFeature/src/main/java/org/openapitools/client/ApiClient.java, line 564:

<comment>read(byte[],off,len) violates InputStream contract by returning -1 on zero-length reads at EOF instead of 0</comment>

<file context>
@@ -478,11 +482,119 @@ public static InputStream getResponseBody(HttpResponse<InputStream> response) th
+    }
+
+    @Override
+    public int read(byte[] b, int off, int len) throws IOException {
+      if (!fillBuffer()) {
+        return -1;
</file context>

Suggested change

	public int read(byte[] b, int off, int len) throws IOException {
	@Override
	public int read(byte[] b, int off, int len) throws IOException {
	if (len == 0) {
	return 0;
	}
	if (!fillBuffer()) {
	return -1;
	}