Add CLDC11 compatibility check workflow and APIChecker tool

This change introduces a new GitHub Actions pipeline (`.github/workflows/cldc11-check.yml`) that verifies `Ports/CLDC11` is a binary compatible subset of JavaSE 11 and `vm/JavaAPI`.

It also adds a custom tool `scripts/api-checker`, implemented in Java using ASM, to perform the binary compatibility analysis (checking classes, methods, fields, superclasses, and interfaces). The tool generates a report of extra APIs present in the reference (e.g., `vm/JavaAPI`) as requested.

Author: google-labs-jules[bot]

.github/workflows/cldc11-check.yml

@@ -0,0 +1,57 @@
+name: CLDC11 Compatibility Check
+
+on:
+  push:
+    paths:
+      - 'Ports/CLDC11/**'
+      - 'vm/JavaAPI/**'
+      - '.github/workflows/cldc11-check.yml'
+  pull_request:
+    paths:
+      - 'Ports/CLDC11/**'
+      - 'vm/JavaAPI/**'
+      - '.github/workflows/cldc11-check.yml'
+
+jobs:
+  check-cldc11:
+    runs-on: ubuntu-latest
+    container:
+      image: ghcr.io/codenameone/codenameone/ci-container:latest
+    defaults:
+      run:
+        shell: bash
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Build APIChecker
+        run: mvn package -f scripts/api-checker/pom.xml
+
+      - name: Build Ports/CLDC11
+        run: |
+          cd Ports/CLDC11
+          ant jar
+
+      - name: Build vm/JavaAPI
+        run: mvn package -f vm/JavaAPI/pom.xml -DskipTests
+
+      - name: Check CLDC11 vs JavaSE 11
+        run: |
+          $JAVA11_HOME/bin/java -jar scripts/api-checker/target/api-checker-1.0-SNAPSHOT.jar \
+            --subject Ports/CLDC11/dist/CLDC11.jar \
+            --reference java11
+
+      - name: Check CLDC11 vs vm/JavaAPI
+        run: |
+          $JAVA11_HOME/bin/java -jar scripts/api-checker/target/api-checker-1.0-SNAPSHOT.jar \
+            --subject Ports/CLDC11/dist/CLDC11.jar \
+            --reference vm/JavaAPI/target/classes \
+            --report extra_apis_report.json
+
+      - name: Upload Extra APIs Report
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: extra-apis-report
+          path: extra_apis_report.json

scripts/api-checker/pom.xml

@@ -0,0 +1,64 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.codename1.tools</groupId>
+    <artifactId>api-checker</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <properties>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
+        <asm.version>9.6</asm.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.ow2.asm</groupId>
+            <artifactId>asm</artifactId>
+            <version>${asm.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.ow2.asm</groupId>
+            <artifactId>asm-tree</artifactId>
+            <version>${asm.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.ow2.asm</groupId>
+            <artifactId>asm-commons</artifactId>
+            <version>${asm.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>2.15.2</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>3.5.0</version>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                        <configuration>
+                            <transformers>
+                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                    <mainClass>com.codename1.apichecker.APIChecker</mainClass>
+                                </transformer>
+                            </transformers>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>