Message-ID: <gh-pgjdbc-pgjdbc-4068@github.com>
From: "mblakley-casana (@mblakley-casana)" <noreply+mblakley-casana@github.com>
To: "pgjdbc/pgjdbc" <noreply+pgjdbc-pgjdbc@github.com>
Date: Wed, 13 May 2026 21:02:23 +0000
Subject: [pgjdbc/pgjdbc] issue #4068: Android/ART cannot load pgjdbc 42.2.10+ because maxResultBuffer parser references java.lang.management.ManagementFactory
List-Id: <gh-pgjdbc-pgjdbc.github.com>
X-GitHub-Author-Id: 163172869
X-GitHub-Author-Login: mblakley-casana
X-GitHub-Issue: 4068
X-GitHub-Repo: pgjdbc/pgjdbc
X-GitHub-State: closed
X-GitHub-Type: issue
X-GitHub-Url: https://github.com/pgjdbc/pgjdbc/issues/4068
Content-Type: text/plain; charset=utf-8

**I'm submitting a ...**

- [x] bug report
- [ ] feature request

**Describe the issue**

Android's ART runtime does not provide the Java SE `java.lang.management` package. Since pgjdbc 42.2.10, `org.postgresql.util.PGPropertyMaxResultBufferParser` has a verifier-visible reference to `java.lang.management.ManagementFactory`.

That makes current pgjdbc releases fail to load in Android instrumentation/test APKs even when the application never configures `maxResultBuffer` and never uses the percentage form of that property.

**Driver Version?**

42.2.10 and newer, including current 42.7.x releases.

42.2.8 does not have `PGPropertyMaxResultBufferParser` and is still loadable on Android for this use case.

**Java Version?**

Android Runtime (ART), reproduced on an Android API 34 emulator.

This is not an Oracle/OpenJDK Java SE runtime issue; `java.lang.management.ManagementFactory` exists there.

**OS Version?**

Android API 34 emulator. The underlying issue applies to Android runtimes that omit `java.lang.management`.

**PostgreSQL Version?**

Not relevant to the class-loading failure. The driver fails before a query is needed.

**To Reproduce**

1. Add pgjdbc version >= 42.2.10 to an Android instrumentation test APK.
2. In test code, load the driver or open a normal JDBC connection:

```java
Class.forName("org.postgresql.Driver");
// or DriverManager.getConnection("jdbc:postgresql://...", user, password)
```

3. Run the instrumentation test on Android.

**Expected behaviour**

The driver should load when `maxResultBuffer` is unset.

**Actual behaviour**

Android fails while resolving the pgjdbc class graph because `java.lang.management.ManagementFactory` is unavailable:

```text
java.lang.NoClassDefFoundError: Failed resolution of: Ljava/lang/management/ManagementFactory;
```

**Logs**

Representative Android failure:

```text
java.lang.NoClassDefFoundError: Failed resolution of: Ljava/lang/management/ManagementFactory;
```

**Context**

We use pgjdbc from Android end-to-end tests to perform direct PostgreSQL setup/teardown through a helper class. This is test-only usage, not production app database access.

The Android runtime omits JMX/`java.lang.management`, so a static class reference to `ManagementFactory` prevents the driver class graph from loading. The `maxResultBuffer` percentage syntax is a JVM heap convenience feature, but the driver currently touches the class even when `maxResultBuffer` is unset.

**Suggested fix**

Avoid direct/verifier-visible references to `java.lang.management` from production driver classes.

`PGPropertyMaxResultBufferParser` can look up `ManagementFactory`, `MemoryMXBean`, and `MemoryUsage` reflectively only when heap introspection is actually needed. If those classes are unavailable:

- unset `maxResultBuffer` should continue to parse as disabled
- byte values such as `100M` should remain usable, without heap-based capping
- percentage values such as `10pct` should fail with a clear `PSQLException`

I have a small patch prepared with tests for the missing-management-runtime path.