I was having same issue then realized that the version of commons-io getting picked up was lower than what I need (2.4)....I need to Override the already managed version as below to get the right one picked up:

<dependency>
     <groupId>commons-io</groupId>
     <artifactId>commons-io</artifactId>
     <version>2.4</version>
 </dependency>

it started working now. I downloaded commons-io-2.4 from a different resource and imported to my project. Thanks

From this link, you should change the line in gradle file from

api 'org.apache.directory.studio:org.apache.commons.io:2.6'

to

compile group: 'commons-io', name: 'commons-io', version: '2.6'

Update: New api keyword is exactly the same as the old compile keyword. To get rid of warning from compiler then use.

api group: 'commons-io', name: 'commons-io', version: '2.6'

This is the problem:

Copyimport org.apache.commons.math3;

That's trying to import a package - you can't do that. You have to either use a wildcard import:

Copyimport org.apache.commons.math3.*;

or import a specific type:

Copyimport org.apache.commons.math3.SomeTypeHere;

In your case it sounds like you actually want:

Copyimport org.apache.commons.math3.distribution.EnumeratedIntegerDistribution;

I've tried a sample class with just that import and the jar file downloaded from Apache, and it works fine.

if you are using target sdk as 23 add below code in your build.gradle

android{
    compileSdkVersion 23
    buildToolsVersion '23.0.1'
    useLibrary  'org.apache.http.legacy'
}

and change your buildscript to

classpath 'com.android.tools.build:gradle:1.3.0' 

for more info follow this link

Try running the following commands and examine the output:

$ mvn dependency:tree
$ mvn help:effective-pom

Look for commons-lang, maybe something will draw your attention like excludes or dependency overrides. Also, is:

$ mvn dependency:copy-dependencies

copying commons-lang JAR to your target?

i were also facing the same issue. it was resolved by adding commons-codec.jar

you may download it from http://mvnrepository.com/artifact/commons-codec/commons-codec/1.7

http://commons.apache.org/proper/commons-lang/ states the following:

Note that Lang 3.0 (and subsequent versions) use a different package (org.apache.commons.lang3) than the previous versions (org.apache.commons.lang), allowing it to be used at the same time as an earlier version.

So change the package accordingly, or heed Richard Tingle's advice and left click the error+light bulb icon in the gutter (were line numbers are shown) and choose "Add import for...".

import org.apache.commons.lang3.StringUtils;