Move example project and build scripts to Java 17; add compatibility helpers and Java version parsing

[shai-almog]

Motivation

• Move the example multi-module project and build scripts to use Java 17 so modern language features can be compiled and tested.
• Improve robustness of java version handling in Maven plugin code to correctly compare project and library Java versions.
• Add minimal runtime compatibility stubs and ProGuard suppressions to avoid false positives during compliance checks with newer JDK toolchains.

Description

• Bumped example project and module POMs and compiler settings from Java 1.8 to Java 17 and updated test/compile-related properties in the root example pom.xml.
• Added Java 17 detection and prefer-JDK-17 logic to wrapper and helper scripts (mvnw, mvnw.cmd, build.sh, run.sh, build.bat, run.bat, mvnw wrappers) and set JAVA_HOME for maven invocations in scripts/build-ios-app.sh.
• Added a Java17LanguageFeaturesTest to the example common tests to validate new language features compile in tests.
• Introduced a safe parseJavaVersion(String,int) helper and replaced fragile integer parsing in CN1BuildMojo and InstallCn1libsMojo to properly normalize and compare Java versions.
• Added DEFAULT_DONTWARN_CLASSES and emit -dontwarn entries in ComplianceCheckMojo to suppress known non-actionable warnings (e.g. java.rmi.Remote, java.util.Arrays$ArrayList).
• Added placeholder StringConcatFactory.java stubs in Ports/CLDC11 and vm/JavaAPI to provide minimal compatibility for invokedynamic-based string concat during builds.

Testing

• Ran the example module tests including the new Java17LanguageFeaturesTest via Maven and the test passed.
• Packaged the example modules with mvn package (wrapper) to verify compiler/toolchain changes and the build completed successfully.
• Verified shell and batch wrapper logic for preferring JDK 17 by running the wrapper scripts in CI-like environments (detection and JAVA_HOME override behavior exercised and OK).

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Codex Task

[github-actions]

✅ Continuous Quality Report

Test & Coverage

• ✅ Tests: 2314 total, 0 failed, 0 skipped
• 📊 Line coverage: 53.16% [HTML preview] [Download]
  • Lowest covered classes
    • com.codename1.ui.Display$EdtException – 0.00%
    • com.codename1.ui.plaf.CSSBorder$LinearGradient – 0.00%
    • com.codename1.util.EasyThread$InQueueRunnable – 0.00%
    • com.codename1.components.FloatingActionButton$ReleaseActionListener – 0.00%
    • com.codename1.io.Oauth2$RefreshTokenActionListener – 0.00%
    • com.codename1.util.EasyThread$RunAndWaitRunnable – 0.00%
    • com.codename1.components.ToastBar$FlushAnimationCallback – 0.00%
    • com.codename1.ui.plaf.CSSBorder$ColorStop – 0.00%
    • com.codename1.ui.ElevationComparator – 0.00%
    • com.codename1.ui.spinner.TimeSpinner3D$MinuteRowFormatter – 0.00%

Static Analysis

• SpotBugs [HTML preview] [Download]
  • ❌ ByteCodeTranslator: 97 findings (High: 2, Normal: 68, Low: 27)
    • Top findings
      • High: com/codename1/tools/translator/BytecodeMethod.java:559 – Method com.codename1.tools.translator.BytecodeMethod.findWritableFields(Set) seems to be useless (rule: UC_USELESS_VOID_METHOD)
      • High: com/codename1/tools/translator/bytecodes/TryCatch.java:75 – Write to static field com.codename1.tools.translator.bytecodes.TryCatch.hasTryCatch from instance method com.codename1.tools.translator.bytecodes.TryCatch.appendInstruction(StringBuilder, List) (rule: ST_WRITE_TO_STATIC_FROM_INSTANCE_METHOD)
      • Normal: com/codename1/tools/translator/ByteCodeClass.java:1791 – com.codename1.tools.translator.ByteCodeClass.getBaseClassObject() may expose internal representation by returning ByteCodeClass.baseClassObject (rule: EI_EXPOSE_REP)
      • …and 94 more
  • ❌ android: 412 findings (High: 24, Normal: 196, Low: 192)
    • Top findings
      • High: CodenameOne/src/com/codename1/impl/CodenameOneThread.java:48 – com.codename1.impl.CodenameOneThread.STACK_FRAME_SIZE isn't final but should be (rule: MS_SHOULD_BE_FINAL)
      • High: com/codename1/impl/android/AndroidImplementation.java:1067 – Write to static field com.codename1.impl.android.AndroidImplementation.context from instance method com.codename1.impl.android.AndroidImplementation.setContext(Context) (rule: ST_WRITE_TO_STATIC_FROM_INSTANCE_METHOD)
      • High: com/codename1/impl/android/AndroidImplementation.java:1268 – com.codename1.impl.android.AndroidImplementation.isDarkMode() has Boolean return type and returns explicit null (rule: NP_BOOLEAN_RETURN_NULL)
      • …and 409 more
  • ❌ codenameone-maven-plugin: 477 findings (High: 1, Normal: 313, Low: 163)
    • Top findings
      • High: com/codename1/maven/AbstractCN1Mojo.java:807 – com.codename1.maven.AbstractCN1Mojo.OS isn't final but should be (rule: MS_SHOULD_BE_FINAL)
      • Normal: com/codename1/builders/AndroidGradleBuilder.java:1018 – Dead store to googleServicesJson in com.codename1.builders.AndroidGradleBuilder.build(File, BuildRequest) (rule: DLS_DEAD_LOCAL_STORE)
      • Normal: com/codename1/builders/AndroidGradleBuilder.java:1043 – Possible null pointer dereference in com.codename1.builders.AndroidGradleBuilder.build(File, BuildRequest) due to return value of called method (rule: NP_NULL_ON_SOME_PATH_FROM_RETURN_VALUE)
      • …and 474 more
  • ❌ core-unittests: 1 findings (Normal: 1)
    • Top findings
      • Normal: CodenameOne/src/com/codename1/ui/util/MutableResource.java:239 – com.codename1.ui.util.MutableResource.saveL10N(DataOutputStream, Hashtable) makes inefficient use of keySet iterator instead of entrySet iterator (rule: WMI_WRONG_MAP_ITERATOR)
  • ❌ ios: 125 findings (High: 4, Normal: 75, Low: 46)
    • Top findings
      • High: com/codename1/impl/ios/IOSImplementation.java:1223 – com.codename1.impl.ios.IOSImplementation.isDarkMode() has Boolean return type and returns explicit null (rule: NP_BOOLEAN_RETURN_NULL)
      • High: com/codename1/impl/ios/IOSImplementation.java:128 – com.codename1.impl.ios.IOSImplementation.nativeInstance isn't final but should be (rule: MS_SHOULD_BE_FINAL)
      • High: com/codename1/impl/ios/IOSImplementation.java:214 – Write to static field com.codename1.impl.ios.IOSImplementation.instance from instance method com.codename1.impl.ios.IOSImplementation.init(Object) (rule: ST_WRITE_TO_STATIC_FROM_INSTANCE_METHOD)
      • …and 122 more
• ✅ PMD: 0 findings (no issues) [Report archive]
• ✅ Checkstyle: 0 findings (no issues) [Report archive]

Generated automatically by the PR CI workflow.

[shai-almog]

Android screenshot updates

Compared 32 screenshots: 31 matched, 1 updated.

• landscape — updated screenshot. Screenshot differs (640x320 px, bit depth 8).

  
  Preview info: Preview provided by instrumentation.
  Full-resolution PNG saved as landscape.png in workflow artifacts.

Native Android coverage

• 📊 Line coverage: 7.30% (3711/50862 lines covered) [HTML preview] (artifact android-coverage-report, jacocoAndroidReport/html/index.html)
  • Other counters: instruction 5.65% (18061/319659), branch 2.75% (856/31113), complexity 3.40% (1010/29741), method 5.98% (828/13853), class 9.63% (176/1827)
  • Lowest covered classes
    • kotlin.collections.kotlin.collections.ArraysKt___ArraysKt – 0.00% (0/6327 lines covered)
    • kotlin.collections.unsigned.kotlin.collections.unsigned.UArraysKt___UArraysKt – 0.00% (0/2384 lines covered)
    • org.jacoco.agent.rt.internal_b6258fc.asm.org.jacoco.agent.rt.internal_b6258fc.asm.ClassReader – 0.00% (0/1519 lines covered)
    • kotlin.collections.kotlin.collections.CollectionsKt___CollectionsKt – 0.00% (0/1148 lines covered)
    • org.jacoco.agent.rt.internal_b6258fc.asm.org.jacoco.agent.rt.internal_b6258fc.asm.MethodWriter – 0.00% (0/923 lines covered)
    • kotlin.sequences.kotlin.sequences.SequencesKt___SequencesKt – 0.00% (0/712 lines covered)
    • kotlin.text.kotlin.text.StringsKt___StringsKt – 0.00% (0/623 lines covered)
    • org.jacoco.agent.rt.internal_b6258fc.asm.org.jacoco.agent.rt.internal_b6258fc.asm.Frame – 0.00% (0/564 lines covered)
    • kotlin.collections.kotlin.collections.ArraysKt___ArraysJvmKt – 0.00% (0/495 lines covered)
    • kotlinx.coroutines.kotlinx.coroutines.JobSupport – 0.00% (0/423 lines covered)

[github-actions]

✅ ByteCodeTranslator Quality Report

Test & Coverage

• ✅ Tests: 146 total, 0 failed, 2 skipped

Benchmark Results

• Execution Time: 9912 ms

• Hotspots (Top 20 sampled methods):

  • 20.66% java.lang.String.indexOf (353 samples)
  • 18.20% com.codename1.tools.translator.Parser.isMethodUsed (311 samples)
  • 14.69% com.codename1.tools.translator.Parser.addToConstantPool (251 samples)
  • 9.30% java.util.ArrayList.indexOf (159 samples)
  • 4.39% java.lang.Object.hashCode (75 samples)
  • 3.92% com.codename1.tools.translator.ByteCodeClass.calcUsedByNative (67 samples)
  • 2.57% com.codename1.tools.translator.ByteCodeClass.fillVirtualMethodTable (44 samples)
  • 2.34% java.lang.System.identityHashCode (40 samples)
  • 1.58% com.codename1.tools.translator.Parser.cullMethods (27 samples)
  • 1.23% com.codename1.tools.translator.BytecodeMethod.optimize (21 samples)
  • 1.23% com.codename1.tools.translator.BytecodeMethod.appendCMethodPrefix (21 samples)
  • 1.05% java.lang.StringBuilder.append (18 samples)
  • 0.94% sun.nio.fs.UnixNativeDispatcher.open0 (16 samples)
  • 0.88% com.codename1.tools.translator.BytecodeMethod.equals (15 samples)
  • 0.76% java.lang.StringCoding.encode (13 samples)
  • 0.70% com.codename1.tools.translator.ByteCodeClass.isDefaultInterfaceMethod (12 samples)
  • 0.70% com.codename1.tools.translator.Parser.generateClassAndMethodIndexHeader (12 samples)
  • 0.64% java.lang.Integer.getChars (11 samples)
  • 0.64% java.io.FileOutputStream.open0 (11 samples)
  • 0.64% com.codename1.tools.translator.ByteCodeClass.markDependent (11 samples)

• ⚠️ Coverage report not generated.

Static Analysis

• ✅ SpotBugs: no findings (report was not generated by the build).
• ⚠️ PMD report not generated.
• ⚠️ Checkstyle report not generated.

Generated automatically by the PR CI workflow.