java.lang.ClassNotFoundException: io.reactivex.ObservableOnSubscribe

[zhuruyi2013]

• [x] Please include the library version number, including the minor and patch version, in the issue text. In addition, if you'd include the major version in the title (such as 2.x) that would be great.

io.reactivex.rxjava2:rxjava:2.1.0

AndroidStudio3.0.1 gradle 3.0.1 ----------code-------

import com.android.ddmlib.Log;

import io.reactivex.Observable;
import io.reactivex.ObservableEmitter;
import io.reactivex.ObservableOnSubscribe;
import io.reactivex.Observer;
import io.reactivex.disposables.Disposable;

/**
 * Created by zry on 2018/1/14.
 */

public class HelloMyWorld {
    private static final String TAG = "HelloMyWorld";

    public static void main(String[] args) {
        Observable.create(new ObservableOnSubscribe<Integer>() {
            @Override
            public void subscribe(ObservableEmitter<Integer> emitter) throws Exception {
                emitter.onNext(1);
                emitter.onNext(2);
                emitter.onNext(3);
                emitter.onComplete();
            }
        }).subscribe(new Observer<Integer>() {
            @Override
            public void onSubscribe(Disposable d) {
                Log.d(TAG, "subscribe");
            }

            @Override
            public void onNext(Integer value) {
                Log.d(TAG, "" + value);
            }

            @Override
            public void onError(Throwable e) {
                Log.d(TAG, "error");
            }

            @Override
            public void onComplete() {
                Log.d(TAG, "complete");
            }
        });
    }
}

-------------error----------------

"/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java" "-javaagent:/Applications/Android Studio.app/Contents/lib/idea_rt.jar=50597:/Applications/Android Studio.app/Contents/bin" -Dfile.encoding=UTF-8 -classpath "/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/charsets.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/jaccess.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/localedata.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/sunec.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/jce.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/jsse.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/management-agent.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/resources.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/jre/lib/rt.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/lib/dt.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/lib/jconsole.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/lib/sa-jdi.jar:/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/lib/tools.jar:/Users/zhuruyi/dffc/tvmobile/javademo/build/classes/java/main" com.rxjava2demo.HelloMyWorld
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.NoClassDefFoundError: io/reactivex/ObservableOnSubscribe
    at java.lang.Class.getDeclaredMethods0(Native Method)
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
    at java.lang.Class.privateGetMethodRecursive(Class.java:3048)
    at java.lang.Class.getMethod0(Class.java:3018)
    at java.lang.Class.getMethod(Class.java:1784)
    at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)
    at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)
Caused by: java.lang.ClassNotFoundException: io.reactivex.ObservableOnSubscribe
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 7 more

Process finished with exit code 1

[zhuruyi2013]

-----------code---------------

Observable.just(1).subscribe(new Consumer<Integer>() {
            @Override
            public void accept(Integer integer) throws Exception {
                Log.d(TAG, "i=" + integer);
            }
        });

----------error------------------

Exception in thread "main" java.lang.NoClassDefFoundError: io/reactivex/functions/Consumer
    at java.lang.Class.getDeclaredMethods0(Native Method)
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
    at java.lang.Class.privateGetMethodRecursive(Class.java:3048)
    at java.lang.Class.getMethod0(Class.java:3018)
    at java.lang.Class.getMethod(Class.java:1784)
    at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)
    at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)
Caused by: java.lang.ClassNotFoundException: io.reactivex.functions.Consumer
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 7 more

i think the detail error does't mean the real error, maybe gradle3.0 can't support rxjava2.0. i create a java module under a androidproject,the build.gradle content as below:

apply plugin: 'java'

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.tools.lint:lint-api:24.5.0'
    implementation 'com.android.tools.lint:lint-checks:24.5.0'

    implementation 'io.reactivex.rxjava2:rxjava:2.1.0'
    implementation 'org.reactivestreams:reactive-streams:1.0.2'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
//    implementation 'org.reactivestreams:reactive-streams-tck:1.0.2'

//    implementation 'io.reactivex.rxjava2:rxandroid:2.0.1'
}

jar {
    manifest {
        attributes("Lint-Registry": "com.dt.lint.MTIssueRegistry")
    }
}

[akarnokd]

This is not an issue with RxJava but with the IDE/project setup you have. You may have to do a clean install of Android Studio and make sure you are using the latest Gradle the IDE supports. Also check the project settings to see if the imported libraries are properly marked as compile-time dependency by the IDE as sometimes they appear as runtime or test dependencies which then fail to run properly.