java.lang.NoClassDefFoundError: java/util/function/BiFunction

using lingua version :

<dependency>
	<groupId>com.github.pemistahl</groupId>
	<artifactId>lingua</artifactId>
	<version>1.0.1</version>
</dependency>

using code :

private static final LanguageDetector detector =
		LanguageDetectorBuilder.fromLanguages(Language.KOREAN, Language.JAPANESE).build();
detector.computeLanguageConfidenceValues("안녕하세요");

error message :

objc[47695]: Class JavaLaunchHelper is implemented in both /Library/Java/JavaVirtualMachines/jdk1.7.0_80.jdk/Contents/Home/bin/java (0x1051664c0) and /Library/Java/JavaVirtualMachines/jdk1.7.0_80.jdk/Contents/Home/jre/lib/libinstrument.dylib (0x1051e04e0). One of the two will be used. Which one is undefined.

java.lang.NoClassDefFoundError: java/util/function/BiFunction

	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
	at com.github.pemistahl.lingua.api.LanguageDetector.addCharCount(LanguageDetector.kt:409)
	at com.github.pemistahl.lingua.api.LanguageDetector.detectLanguageWithRules$lingua(LanguageDetector.kt:234)
	at com.github.pemistahl.lingua.api.LanguageDetector.computeLanguageConfidenceValues(LanguageDetector.kt:145)
	at com.github.pemistahl.lingua.api.LanguageDetector.detectLanguageOf(LanguageDetector.kt:100)
	at com.naver.labs.smt.api.translator.bo.TranslatorBoTest.test(TranslatorBoTest.java:25)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
Caused by: java.lang.ClassNotFoundException: java.util.function.BiFunction
	at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
	... 39 more

[pemistahl]

Hi @levant916, thank you for using Lingua and for opening this issue.

I can confirm that this is a bug. This is because the LanguageDetector uses the Java method java.util.Map.merge() internally which is only supported by Java >= 1.8. I will replace it by an appropriate Kotlin method. After this change, the library should run on Java 1.6 and 1.7 as it was originally intended.

Only the FilesWriter classes will need Java 1.8 at least because I make use of the NIO api. But if you don’t want to create your own language models, you should be fine with Java < 1.8.

[pemistahl]

@roi3363 Can you please open a new issue for your specific problem? In that new issue, please state your project configuration including your build script if any, including any third-party dependencies you are using. Thank you.