Reformat Java sources with open-java-format

[bric3]

What Does This Do

Apply open-java-format 2.98.0.5 to 6,346 Java files with the configuration in #12710.

Representative Formatting Changes

These examples revisit the same methods as #12444, on master revision 3228587fbf0010a3834b47fd2b1c242445c5da2b.

Lambda Pipelines

PluginApplication.java

-        Extension.EXTENSIONS.stream()
-            .filter(ext -> ext.appliesTo(spec))
-            .forEach(
-                ext -> {
+                Extension.EXTENSIONS.stream().filter(ext -> ext.appliesTo(spec)).forEach(ext -> {

Fluent Calls

AdviceGeneratorImpl.java

-      final List<Expression> helperTypes =
-          Arrays.stream(helpers)
-              .map(type -> new StringLiteralExpr(type.getClassName()))
-              .collect(Collectors.toList());
+            final List<Expression> helperTypes = Arrays.stream(helpers)
+                    .map(type -> new StringLiteralExpr(type.getClassName()))
+                    .collect(Collectors.toList());

Nested Callbacks

CoreTracer.java

-    sharedCommunicationObjects.whenReady(
-        () ->
-            AgentTaskScheduler.get()
-                .execute(
-                    () -> {
-                      startMetricsAggregation(config, sco);
-                      maybeStartLogsExport(config);
-                    }));
+        sharedCommunicationObjects.whenReady(() -> AgentTaskScheduler.get().execute(() -> {
+            startMetricsAggregation(config, sco);
+            maybeStartLogsExport(config);
+        }));

Long TableTest rows stay single annotation values, even when they exceed 120 columns. Spotless protects existing off/on regions around the Java and table steps.

Parameter Wrapping

In the same PluginApplication.printReport method, OJF packs the parameters on one continuation line and keeps the closing delimiter beside the final parameter. Prince's default balanced wrapping puts each parameter and the closing delimiter on separate lines. The experiments also use different widths: OJF 120 columns, Prince 100.

    private static void printReport(
            final Configuration configuration, final List<CallSiteResult> result, final boolean failed) {

Switch Blocks

JsonToExpressionConverter.java

OJF joins the opening block with its case label. Prince keeps the original separate line.

-      case "not":
-        {
-          JsonReader.Token token = reader.peek();
+            case "not": {
+                JsonReader.Token token = reader.peek();

Inline Argument Comments

In CoreTracer, OJF keeps the comment attached to its argument:

                    null /* serviceName */,

The Prince experiment moved that comment after the comma onto its own line. This is also one of the earlier formatter regressions checked during this evaluation.

Short Guards and Javadocs

OJF preserves these compact forms in CoreTracer; Prince adds braces to the guard and expands the Javadoc:

            if (this.inUse) return false;

    /** Tracer start time in nanoseconds measured up to a millisecond accuracy */

OJF also retains the blank line between static and regular imports, which the Prince experiment removed.

Motivation

Improve human readability of the source of google java format

Additional Notes

String reflow is disabled and TableTest formatting runs last.

A parsed audit of every changed Java file found no changes to AST node structure, literal values, or canonical table values and row counts.

run with

jbang tooling/VerifyFormatting.java \
    path/to/dd-trace-java-ojf-baseline \
    path/to/dd-trace-java-open-java-format \
    current-pr-java.txt

//JAVA 25
//DEPS org.tabletest:tabletest-formatter-core:1.1.2
import com.sun.source.tree.AnnotationTree;
import com.sun.source.tree.AssignmentTree;
import com.sun.source.tree.BinaryTree;
import com.sun.source.tree.IdentifierTree;
import com.sun.source.tree.ImportTree;
import com.sun.source.tree.LiteralTree;
import com.sun.source.tree.MemberSelectTree;
import com.sun.source.tree.NewArrayTree;
import com.sun.source.tree.ParenthesizedTree;
import com.sun.source.tree.Tree;
import com.sun.source.util.JavacTask;
import com.sun.source.util.TreeScanner;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import javax.tools.Diagnostic;
import javax.tools.DiagnosticCollector;
import javax.tools.JavaFileObject;
import javax.tools.ToolProvider;
import org.tabletest.formatter.config.Config;
import org.tabletest.formatter.core.TableTestFormatter;

/** Audits parsed Java before and after formatting, excluding imports and table padding. */
class VerifyFormatting {
    record Snapshot(List<String> literals, List<String> tables, List<Tree.Kind> structure) {}

    static Map<String, Snapshot> read(Path root, List<String> paths) throws Exception {
        var result = new TreeMap<String, Snapshot>();
        var compiler = ToolProvider.getSystemJavaCompiler();
        var diagnostics = new DiagnosticCollector<JavaFileObject>();
        try (var manager = compiler.getStandardFileManager(diagnostics, null, null)) {
            var files = manager.getJavaFileObjectsFromPaths(
                    paths.stream().map(root::resolve).toList());
            var task = (JavacTask) compiler.getTask(
                    null,
                    manager,
                    diagnostics,
                    List.of("-proc:none", "--enable-preview", "--source", "25"),
                    null,
                    files);
            for (var unit : task.parse()) {
                var literals = new ArrayList<String>();
                var tables = new ArrayList<String>();
                var structure = new ArrayList<Tree.Kind>();
                new TreeScanner<Void, Void>() {
                    public Void scan(Tree node, Void ignored) {
                        if (node instanceof ImportTree) return null;
                        if (node != null) structure.add(node.getKind());
                        return super.scan(node, ignored);
                    }

                    public Void visitLiteral(LiteralTree node, Void ignored) {
                        literals.add(node.getKind() + ":" + node.getValue());
                        return null;
                    }

                    public Void visitAnnotation(AnnotationTree node, Void ignored) {
                        if (!node.getAnnotationType().toString().endsWith("TableTest"))
                            return super.visitAnnotation(node, ignored);
                        var rows = new ArrayList<String>();
                        for (var arg : node.getArguments()) {
                            Tree value = arg instanceof AssignmentTree assignment ? assignment.getExpression() : arg;
                            if (arg instanceof AssignmentTree assignment
                                    && !assignment.getVariable().toString().equals("value")) {
                                scan(arg, ignored);
                                continue;
                            }
                            if (value instanceof NewArrayTree array)
                                for (var row : array.getInitializers()) rows.add(stringValue(row));
                            else rows.add(stringValue(value));
                        }
                        tables.add(rows.size() + ":"
                                + new TableTestFormatter().format(String.join("\n", rows), "", Config.NO_INDENT));
                        return null;
                    }
                }.scan(unit, null);
                result.put(
                        root.relativize(Path.of(unit.getSourceFile().toUri())).toString(),
                        new Snapshot(literals, tables, structure));
            }
        }
        var errors = diagnostics.getDiagnostics().stream()
                .filter(d -> d.getKind() == Diagnostic.Kind.ERROR)
                .toList();
        if (!errors.isEmpty()) throw new AssertionError(errors.toString());
        return result;
    }

    static String stringValue(Tree value) {
        if (value instanceof LiteralTree literal && literal.getValue() instanceof String text) return text;
        if (value instanceof BinaryTree binary && binary.getKind() == Tree.Kind.PLUS)
            return stringValue(binary.getLeftOperand()) + stringValue(binary.getRightOperand());
        if (value instanceof ParenthesizedTree parens) return stringValue(parens.getExpression());
        if (value instanceof IdentifierTree || value instanceof MemberSelectTree) return "${" + value + "}";
        throw new AssertionError("Unsupported TableTest value: " + value);
    }

    public static void main(String[] args) throws Exception {
        if (args.length < 3 || args.length > 4 || (args.length == 4 && !args[3].equals("tables"))) {
            throw new IllegalArgumentException(
                    "Usage: VerifyFormatting.java before-root after-root paths-file [tables]");
        }
        var paths = Files.readAllLines(Path.of(args[2]));
        var before = read(Path.of(args[0]).toAbsolutePath(), paths);
        var after = read(Path.of(args[1]).toAbsolutePath(), paths);
        int failures = 0;
        for (var path : paths) {
            var a = before.get(path);
            var b = after.get(path);
            if (args.length > 3 ? !a.tables.equals(b.tables) : !a.equals(b)) {
                System.out.println(path + " literals=" + a.literals.equals(b.literals) + " tables="
                        + a.tables.equals(b.tables) + " structure=" + a.structure.equals(b.structure));
                failures++;
            }
        }
        System.out.println("Audited " + paths.size() + " Java files; differences=" + failures);
        if (failures != 0) throw new AssertionError("Formatter changed parsed source");
    }
}

Contributor Checklist

• Format the title according to the contribution guidelines
• Assign the type: and (comp: or inst:) labels in addition to any other useful labels
• Avoid using close, fix, or any linking keywords when referencing an issue
  Use solves instead, and assign the PR milestone to the issue
• Update the CODEOWNERS file on source file addition, migration, or deletion
• Update public documentation with any new configuration flags or behaviors
• Once approved, use merge queue to merge the PR

[datadog-datadog-prod-us1-2]

🎯 Code Coverage (details)
• Patch Coverage: 59.57%
• Overall Coverage: 59.37%

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 12092cc | Docs | Give us feedback!}

[pr-commenter]

Debugger benchmarks

Parameters

	Baseline	Candidate
baseline_or_candidate	baseline	candidate
ci_job_date	1790871680	1790871995
end_time	2026-10-01T16:22:47	2026-10-01T16:28:03
git_branch	master	bdu/reformat-with-open-java-format
git_commit_sha	8887cb7	12092cc
start_time	2026-10-01T16:21:20	2026-10-01T16:26:36

See matching parameters

	Baseline	Candidate
ci_job_id	2099817008	2099817008
ci_pipeline_id	141695349	141695349
cpu_model	Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz	Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz
git_commit_date	1790869592	1790869592

Summary

Found 0 performance improvements and 5 performance regressions! Performance is the same for 4 metrics, 6 unstable metrics.

scenario	Δ mean agg_http_req_duration_min	Δ mean agg_http_req_duration_p50	Δ mean agg_http_req_duration_p75	Δ mean agg_http_req_duration_p99	Δ mean throughput
scenario:loop	worse [+462.557µs; +561.146µs] or [+6.152%; +7.463%]	worse [+464.916µs; +565.959µs] or [+6.140%; +7.474%]	worse [+456.172µs; +564.704µs] or [+5.995%; +7.421%]	worse [+447.733µs; +593.550µs] or [+5.814%; +7.708%]	worse [-10.024op/s; -5.814op/s] or [-7.719%; -4.476%]

See unchanged results

scenario	Δ mean agg_http_req_duration_min	Δ mean agg_http_req_duration_p50	Δ mean agg_http_req_duration_p75	Δ mean agg_http_req_duration_p99	Δ mean throughput
scenario:noprobe	unstable [-76.693µs; +42.835µs] or [-22.587%; +12.615%]	unstable [-82.507µs; +52.365µs] or [-22.269%; +14.134%]	unstable [-107.074µs; +65.755µs] or [-27.346%; +16.794%]	unstable [-628.190µs; +213.941µs] or [-44.560%; +15.176%]	same
scenario:basic	same	same	same	unstable [-122.373µs; +132.719µs] or [-11.647%; +12.632%]	unstable [-216.776op/s; +111.068op/s] or [-9.321%; +4.776%]

Request duration reports for reports

gantt
    title reports - request duration [CI 0.99] : candidate=None, baseline=None
    dateFormat X
    axisFormat %s
section baseline
noprobe (370.497 µs) : 294, 447
.   : milestone, 370,
basic (325.191 µs) : 319, 332
.   : milestone, 325,
loop (7.572 ms) : 7552, 7592
.   : milestone, 7572,
section candidate
noprobe (355.426 µs) : 307, 404
.   : milestone, 355,
basic (327.516 µs) : 321, 334
.   : milestone, 328,
loop (8.087 ms) : 8024, 8151
.   : milestone, 8087,

Loading

• baseline results

Scenario	Request median duration [CI 0.99]
noprobe	370.497 µs [293.977 µs, 447.017 µs]
basic	325.191 µs [318.634 µs, 331.748 µs]
loop	7.572 ms [7.552 ms, 7.592 ms]

• candidate results

Scenario	Request median duration [CI 0.99]
noprobe	355.426 µs [306.898 µs, 403.954 µs]
basic	327.516 µs [321.455 µs, 333.576 µs]
loop	8.087 ms [8.024 ms, 8.151 ms]

[dd-octo-sts]

🟢 Java Benchmark SLOs — All performance SLOs passed

Suite	Status
Startup	🟢 pass

SLO thresholds are defined here based on automatically generated metrics. A warning is raised when results are within 5% of the threshold.

PR vs. master results

Scenario	Candidate	master	Δ (95% CI of mean)
startup:insecure-bank:iast:Agent	14.02 s	14.04 s	[-0.8%; +0.5%] (no difference)
startup:insecure-bank:tracing:Agent	12.94 s	12.99 s	[-1.1%; +0.4%] (no difference)
startup:petclinic:appsec:Agent	17.20 s	17.03 s	[+0.2%; +1.8%] (maybe worse)
startup:petclinic:iast:Agent	16.98 s	16.92 s	[-0.4%; +1.2%] (no difference)
startup:petclinic:profiling:Agent	16.63 s	16.61 s	[-0.9%; +1.1%] (no difference)
startup:petclinic:sca:Agent	17.10 s	16.97 s	[-0.3%; +1.8%] (no difference)
startup:petclinic:tracing:Agent	16.33 s	16.22 s	[-0.3%; +1.7%] (no difference)

Commit: 12092cc1 · CI Pipeline · Benchmarking Platform UI

---

Load and DaCapo benchmarks can be triggered manually in the GitLab pipeline. Results will appear in the Benchmarking Platform UI after completion.

[pr-commenter]

Kafka / producer-benchmark

Parameters

	Baseline	Candidate
baseline_or_candidate	baseline	candidate
git_branch	bdu/use-open-java-format	bdu/reformat-with-open-java-format
git_commit_date	1790867285	1790867289
git_commit_sha	7206293	09403da

See matching parameters

	Baseline	Candidate
ci_job_date	1790868824	1790868824
ci_job_id	2099444991	2099444991
ci_pipeline_id	141669547	141669547
cpu_model	Intel(R) Xeon(R) Platinum 8175M CPU @ 2.50GHz	Intel(R) Xeon(R) Platinum 8175M CPU @ 2.50GHz
jdkVersion	11.0.31	11.0.31
jmhVersion	1.36	1.36
jvm	/usr/lib/jvm/java-11-openjdk-amd64/bin/java	/usr/lib/jvm/java-11-openjdk-amd64/bin/java
jvmArgs	-Dhttp.proxyHost=127.0.0.1 -Dhttp.proxyPort=15002 -Dhttps.proxyHost=127.0.0.1 -Dhttps.proxyPort=15002 -Dhttp.nonProxyHosts=localhost	*.localhost
kernel_version	Linux runner-zfyrx7zua-project-304-concurrent-0-tnrms8ab 6.8.0-1031-aws #33~22.04.1-Ubuntu SMP Thu Jun 26 14:22:30 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux	Linux runner-zfyrx7zua-project-304-concurrent-0-tnrms8ab 6.8.0-1031-aws #33~22.04.1-Ubuntu SMP Thu Jun 26 14:22:30 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
vmName	OpenJDK 64-Bit Server VM	OpenJDK 64-Bit Server VM
vmVersion	11.0.31+11-post-1ubuntu1-22.04.2-Ubuntu	11.0.31+11-post-1ubuntu1-22.04.2-Ubuntu

Summary

Found 0 performance improvements and 0 performance regressions! Performance is the same for 3 metrics, 0 unstable metrics.

See unchanged results

scenario	Δ mean throughput
scenario:not-instrumented/KafkaProduceBenchmark.benchProduce	same
scenario:only-tracing-dsm-disabled-benchmarks/KafkaProduceBenchmark.benchProduce	same
scenario:only-tracing-dsm-enabled-benchmarks/KafkaProduceBenchmark.benchProduce	unsure [-4987.127op/s; -37.879op/s] or [-3.616%; -0.027%]

[pr-commenter]

Kafka / consumer-benchmark

Parameters

	Baseline	Candidate
baseline_or_candidate	baseline	candidate
git_branch	bdu/use-open-java-format	bdu/reformat-with-open-java-format
git_commit_date	1790869587	1790869592
git_commit_sha	76c0948	12092cc

See matching parameters

	Baseline	Candidate
ci_job_date	1790872262	1790872262
ci_job_id	2099817003	2099817003
ci_pipeline_id	141695349	141695349
cpu_model	Intel(R) Xeon(R) Platinum 8175M CPU @ 2.50GHz	Intel(R) Xeon(R) Platinum 8175M CPU @ 2.50GHz
jdkVersion	11.0.31	11.0.31
jmhVersion	1.36	1.36
jvm	/usr/lib/jvm/java-11-openjdk-amd64/bin/java	/usr/lib/jvm/java-11-openjdk-amd64/bin/java
jvmArgs	-Dhttp.proxyHost=127.0.0.1 -Dhttp.proxyPort=15002 -Dhttps.proxyHost=127.0.0.1 -Dhttps.proxyPort=15002 -Dhttp.nonProxyHosts=localhost	*.localhost
kernel_version	Linux runner-zfyrx7zua-project-304-concurrent-0-0uqfxbiv 6.8.0-1031-aws #33~22.04.1-Ubuntu SMP Thu Jun 26 14:22:30 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux	Linux runner-zfyrx7zua-project-304-concurrent-0-0uqfxbiv 6.8.0-1031-aws #33~22.04.1-Ubuntu SMP Thu Jun 26 14:22:30 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
vmName	OpenJDK 64-Bit Server VM	OpenJDK 64-Bit Server VM
vmVersion	11.0.31+11-post-1ubuntu1-22.04.2-Ubuntu	11.0.31+11-post-1ubuntu1-22.04.2-Ubuntu

Summary

Found 0 performance improvements and 0 performance regressions! Performance is the same for 3 metrics, 0 unstable metrics.

See unchanged results

scenario	Δ mean throughput
scenario:not-instrumented/KafkaConsumerBenchmark.benchConsume	same
scenario:only-tracing-dsm-disabled-benchmarks/KafkaConsumerBenchmark.benchConsume	same
scenario:only-tracing-dsm-enabled-benchmarks/KafkaConsumerBenchmark.benchConsume	unsure [+495.053op/s; +8009.174op/s] or [+0.303%; +4.906%]