title: Error while adding another table in room database
body: <p>I already was using room database in my application. Now I have migrated my project to androidX, so dependencies are changed.</p>
  
  <p>Now when I am adding a table and trying to run the project, I am getting an error for multiple files:</p>
  
  <pre><code>error: cannot find symbol class BR
  </code></pre>
  
  <p>Here is my model class:</p>
  
  <pre><code>@Keep
  @Entity
  public class Notification {
      private String title;
      private String body;
  
      public Notification(String title, String body) {
          this.title = title;
          this.body = body;
      }
  
      public String getTitle() {
          return title;
      }
  
      public void setTitle(String title) {
          this.title = title;
      }
  
      public String getBody() {
          return body;
      }
  
      public void setBody(String body) {
          this.body = body;
      }
  }
  </code></pre>
  
  <p>Here is my NotificationDao Class:</p>
  
  <pre><code>   public abstract class NotificationDao {
      @Insert(onConflict = REPLACE)
      public abstract void insert(Notification notification);
  
      @Query("DELETE FROM Notification")
      public abstract void deleteAll();
  }
  </code></pre>
  
  <p>Here is the code written for migration:</p>
  
  <pre><code>static final Migration MIGRATION_1_2 = new Migration(1, 2) {
          @Override
          public void migrate(SupportSQLiteDatabase database) {
              database.execSQL("CREATE TABLE IF NOT EXISTS Notification (`title` TEXT, `body` TEXT)");
          }
      };
  </code></pre>
  
  <p>I have increased the version from 1 to 2.</p>
  
  <p>I have added this in build as well.</p>
  
  <pre><code>    Room.databaseBuilder(
                  application,
                  MyDatabase.class,
                  Configuration.DB_NAME
          ).addMigrations(MyDatabase.MIGRATION_1_2).build();
  </code></pre>
  
  <p>app.gradle is:</p>
  
  <pre><code>buildscript {
      repositories {
          maven { url 'https://maven.fabric.io/public' }
      }
  
      dependencies {
          classpath 'io.fabric.tools:gradle:1.+'
      }
  }
  apply plugin: 'com.android.application'
  apply plugin: 'io.fabric'
  
  repositories {
      maven { url 'https://maven.fabric.io/public' }
  }
  
  
  android {
      compileSdkVersion 29
      defaultConfig {
          minSdkVersion 21
          targetSdkVersion 29
          versionCode 211990017
          versionName "2.1"
          testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
          // Write out the current schema of Room
          javaCompileOptions {
              annotationProcessorOptions {
                  arguments = ["room.schemaLocation": "$projectDir/schemas".toString(),]
              }
          }
          vectorDrawables.useSupportLibrary = true
          project.archivesBaseName = "xxxx";
          multiDexEnabled true
          externalNativeBuild {
              cmake {
                  cppFlags "-std=c++11 -fexceptions"
                  arguments "-DANDROID_TOOLCHAIN=clang",
                          "-DANDROID_STL=c++_shared",
                          "-DANDROID_PLATFORM=android-21"
  
              }
          }
  
      }
      sourceSets {
          main {
              jniLibs.srcDirs = ['src/main/jniLibs']
          }
      }
      externalNativeBuild {
          cmake {
              path "CMakeLists.txt"
          }
      }
      signingConfigs {
          release {
              storeFile file("keystores/xxxx")
              storePassword "xxxx"
              keyAlias "xxxx"
              keyPassword "xxxx"
          }
      }
      lintOptions {
          checkReleaseBuilds false
          // Or, if you prefer, you can continue to check for errors in release builds,
          // but continue the build even when errors are found:
          abortOnError false
      }
      buildTypes {
          release {
              minifyEnabled false
              shrinkResources false
              proguardFiles fileTree(dir: "proguard", include: ["*.pro"]).asList().toArray()
              proguardFiles getDefaultProguardFile('proguard-android.txt')
              signingConfig signingConfigs.release
          }
          debug {
              minifyEnabled false
              shrinkResources false
              proguardFiles fileTree(dir: "proguard", include: ["*.pro"]).asList().toArray()
              proguardFiles getDefaultProguardFile('proguard-android.txt')
              signingConfig signingConfigs.release
          }
      }
      dataBinding {
          enabled true
      }
      buildToolsVersion '28.0.3'
      compileOptions {
          sourceCompatibility JavaVersion.VERSION_1_8
          targetCompatibility JavaVersion.VERSION_1_8
      }
      flavorDimensions "environment"
      productFlavors {
          development {
              applicationId "com.emproto.xxxx"
              resValue "string", "content_provider", "com.xxx.xxxx.fileprovider"
          }
          production {
              applicationId "com.xxxx"
              resValue "string", "content_provider", "com.xxxx.fileprovider"
          }
      }
      splits {
          // Configures multiple APKs based on ABI.
          abi {
              // Enables building multiple APKs per ABI.
              enable true
              // By default all ABIs are included, so use reset() and include to specify that we only
              // want APKs for x86 and x86_64.
              // Resets the list of ABIs that Gradle should create APKs for to none.
              reset()
              // Specifies a list of ABIs that Gradle should create APKs for.
              include "x86", "x86_64", "arm64-v8a", "armeabi-v7a"
  
              // Specifies that we do not want to also generate a universal APK that includes all ABIs.
              universalApk true
          }
      }
  
  }
  
  ext.abiCodes = ['x86': 1, 'x86_64': 2, 'armeabi-v7a': 3, 'arm64-v8a': 4]
  import com.android.build.OutputFile
  android.applicationVariants.all { variant -&gt;
      variant.outputs.each { output -&gt;
          def baseVersionCode = project.ext.abiCodes.get(output.getFilter(OutputFile.ABI))
          if (baseVersionCode != null) {
              output.versionCodeOverride = Integer.valueOf(baseVersionCode + variant.versionCode)
          }
      }
  }
  
  ext {
      retrofitVersion = '2.3.0'
      daggerVersion = '2.11'
      supportLibVersion = '28.0.0'
      googleLibVersion = '16.0.1'
      frescoLibVersion = '2.0.0'
      moEngageVersion = '9.8.02'
  }
  
  dependencies {
      implementation fileTree(include: ['*.jar'], dir: 'libs')
      implementation 'androidx.appcompat:appcompat:1.0.0'
      implementation 'com.google.android.material:material:1.0.0'
      implementation 'androidx.cardview:cardview:1.0.0'
      implementation 'androidx.legacy:legacy-support-v13:1.0.0'
      implementation 'androidx.legacy:legacy-support-v4:1.0.0'
      implementation 'androidx.browser:browser:1.0.0'
      implementation 'androidx.recyclerview:recyclerview:1.0.0'
      implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
      implementation 'androidx.exifinterface:exifinterface:1.0.0'
      testImplementation 'junit:junit:4.12'
      androidTestImplementation 'androidx.test.ext:junit:1.1.1'
      androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0'
  
      /*Dagger 2 is a fully static and compile time dependency injection framework*/
      implementation "com.google.dagger:dagger:$daggerVersion"
      annotationProcessor "com.google.dagger:dagger-compiler:$daggerVersion"
      implementation 'javax.annotation:jsr250-api:1.0'
  
      /*LiveData and ViewModel*/
      implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'
  
      /*
                  annotationProcessor "android.arch.lifecycle:compiler:1.1.0"
              */
  
      /*Room*/
      implementation 'androidx.room:room-runtime:2.2.3'
      annotationProcessor 'androidx.room:room-compiler:2.2.3'
  
      // Java8 support for Lifecycles
      implementation 'androidx.lifecycle:lifecycle-common-java8:2.2.0'
  
      /*Retrofit*/
      implementation "com.squareup.retrofit2:retrofit:$retrofitVersion"
      implementation "com.squareup.retrofit2:converter-gson:$retrofitVersion"
  
      /*For loading images from network*/
      implementation "com.facebook.fresco:fresco:$frescoLibVersion"
      implementation "com.facebook.fresco:imagepipeline-okhttp3:$frescoLibVersion"
  
      /*For the left menu*/
      implementation 'com.yarolegovich:sliding-root-nav:1.1.0'
  
      /*For the typing indicator*/
      implementation 'com.github.channguyen:adv:1.0.0'
      implementation 'com.squareup.okhttp3:logging-interceptor:3.9.0'
  
      /*For Graphs */
      implementation 'com.github.PhilJay:MPAndroidChart:v3.0.3'
  
      /*For firebase push notifications */
      implementation "com.google.firebase:firebase-messaging:17.3.4"
      implementation "com.google.firebase:firebase-core:16.0.6"
      /*For Database debugging */
      //    debugImplementation 'com.amitshekhar.android:debug-db:1.0.4'
  
      /*For S - Health */
      implementation files('libs/s-health/samsung-health-data-v1.3.0.jar')
      implementation files('libs/s-health/sdk-v1.0.0.jar')
  
      /*For Google-Fit */
      implementation "com.google.android.gms:play-services-fitness:$googleLibVersion"
      implementation "com.google.android.gms:play-services-auth:$googleLibVersion"
  
      /*Circular floating action bar*/
      implementation 'com.oguzdev:CircularFloatingActionMenu:1.0.2'
  
      // For animated GIF support
      implementation "com.facebook.fresco:animated-gif:$frescoLibVersion"
  
      /*Circular seekbar - Feelings*/
      implementation 'com.github.JesusM:HoloCircleSeekBar:v2.2.2'
  
      /*Circular Layout - Feelings*/
      implementation 'com.github.andreilisun:circular-layout:1.0'
  
      /*For offline log synchronization*/
      implementation 'com.firebase:firebase-jobdispatcher:0.8.5'
  
      /*Wheel picker - RecordCholesterol*/
      implementation 'com.weigan:loopView:0.1.2'
      implementation('com.crashlytics.sdk.android:crashlytics:2.9.3@aar') {
          transitive = true;
      }
  
      /*Image Cropper - Profile Fragment*/
      implementation 'com.theartofdev.edmodo:android-image-cropper:2.7.+'
  
      /*PDF  Viewer - Prescription/Report */
      implementation 'com.github.barteksc:android-pdf-viewer:2.8.2'
      api 'com.thedesigncycle.ui:views:0.3.1'
      implementation 'com.ogaclejapan.smarttablayout:library:1.6.1@aar'
      implementation 'com.getkeepsafe.taptargetview:taptargetview:1.11.0'
      implementation files('libs/omron/jp.co.omron.healthcare.omoron_connect.wrapper-1.3.jar')
      implementation 'com.appsee:appsee-android:+'
      implementation 'com.github.florent37:viewtooltip:1.1.6'
      implementation 'com.asksira.android:cameraviewplus:0.9.5'
      implementation 'me.zhanghai.android.materialratingbar:library:1.3.1'
  
      implementation 'com.priyankvex:smarttextview:1.0.1'
      implementation 'com.github.flipkart-incubator:android-inline-youtube-view:1.0.3'
      implementation 'com.github.varunest:sparkbutton:1.0.6'
  
      implementation 'io.branch.sdk.android:library:3.2.0'
  
  
  
  
      //foo transitions in trel home(doctor names)
      implementation "com.andkulikov:transitionseverywhere:1.8.1"
  
      //AppsFlyer
      implementation 'com.appsflyer:af-android-sdk:4.10.3'
      implementation 'com.android.installreferrer:installreferrer:1.0'
  
      //picasso image loading lib
      implementation 'com.squareup.picasso:picasso:2.5.2'
  
      //Facebook analytics dependency
      implementation 'com.facebook.android:facebook-android-sdk:[4,5)'
  
      //Moengage dependency
      implementation fileTree(dir: 'libs', include: ['*.jar'])
      implementation "com.moengage:moe-android-sdk:$moEngageVersion"
  }
  apply plugin: 'com.google.gms.google-services'
  </code></pre>
  
  <p>How can the error be fixed?</p>