gradle - library duplicates in dependencies

To find duplicate dependencies or its required dependencies, you can visualize library dependencies in tree. Execute gradle command as below.

gradle -q dependencies yourProject:dependencies --configuration compile

Note that, run gradlew in Windows as below.

gradlew -q dependencies yourProject:dependencies --configuration compile

The command result will show you human-readable tree hierarchy of all dependencies as below.

compile - Classpath for compiling the main sources.+--- org.androidannotations:androidannotations-api:3.2+--- com.android.support:support-annotations:22.1.1+--- com.squareup:otto:1.3.6+--- in.srain.cube:grid-view-with-header-footer:1.0.10+--- com.nostra13.universalimageloader:universal-image-loader:1.9.3+--- com.github.chrisbanes.photoview:library:1.2.3+--- org.simpleframework:simple-xml:2.7.1+--- com.google.android.gms:play-services-base:6.5.+ -> 6.5.87+--- project :yourProject|    +--- com.loopj.android:android-async-http:1.4.6|    +--- org.apache.httpcomponents:httpmime:4.2.5|    |    \--- org.apache.httpcomponents:httpcore:4.2.4|    \--- com.google.code.gson:gson:2.3.1+--- project :facebook|    \--- com.android.support:appcompat-v7:22.1.1|         \--- com.android.support:support-v4:22.1.1|              \--- com.android.support:support-annotations:22.1.1 -> 22.2.0

You can see overriden dependencies and decide in mind which ones should be avoided. In above example, last line com.android.support:support-annotations presents overriden from 22.1.1 to 22.2.0 internally.

To avoid duplicates, you can add exclude clauses in each project build.gradle file.

compile('com.github.chrisbanes.photoview:library:1.2.3') {    exclude group: 'com.android.support'}compile('org.simpleframework:simple-xml:2.7.1') {    exclude module: 'stax'    exclude module: 'stax-api'    exclude module: 'xpp3'}compile('com.google.android.gms:play-services-base:6.5.+') {    exclude module: 'support-v4'}

For more information, you can see the tutorial at https://docs.gradle.org/current/userguide/userguide_single.html#sec:listing_dependencies