app/src/main/java/org/fossasia/phimpme/editor/fragment/PaintFragment.java

Use equals() to compare object references.
134
if (v == cancel) {//back button click

app/src/main/java/org/fossasia/phimpme/editor/view/CropImageView.java

Perhaps 'mContext' could be replaced by a local variable.
30
private Context mContext;
Use one line for each declaration, it enhances code readability.
104
float h, w;

app/src/main/java/org/fossasia/phimpme/editor/view/imagezoom/utils/DecodeUtils.java

Use one line for each declaration, it enhances code readability.
139
double w, h;

app/src/main/java/org/fossasia/phimpme/opencamera/Camera/CameraActivity.java

Position literals first in String comparisons
1375
if( immersive_mode.equals("immersive_mode_everything") )

app/src/main/java/org/fossasia/phimpme/opencamera/Camera/TextFormatter.java

The method getGPSString() has an NPath complexity of 236
77
public String getGPSString(String preference_stamp_gpsformat, boolean store_location, Location location, boolean store_geo_direction, double geo_direction) {

app/src/main/java/org/fossasia/phimpme/opencamera/CameraController/CameraController.java

Avoid reassigning parameters such as 'value'
376
SupportedValues checkModeIsSupported(List<String> values, String value, String default_value) {

app/src/main/java/org/fossasia/phimpme/opencamera/UI/DrawPreview.java

Avoid unused private fields such as 'thumbnail_anim_src_rect'.
79
private final RectF thumbnail_anim_src_rect = new RectF();
Avoid reassigning parameters such as 'time'
260
private String getTimeStringFromSeconds(long time) {

build.sh

Tips depend on target shell and yours is unknown. Add a shebang.
1
./gradlew build jacocoTestReport assembleAndroidTest

openCVLibrary24133/src/main/java/org/opencv/core/Mat.java

Method names should not contain underscores
2752
private static native long n_eye(double size_width, double size_height, int type);
Method names should not contain underscores
2757
private static native long n_inv(long nativeObj);

openCVLibrary24133/src/main/java/org/opencv/highgui/VideoCapture.java

Method names should not contain underscores
386
private static native long n_VideoCapture(java.lang.String filename);

openCVLibrary24133/src/main/java/org/opencv/imgproc/Moments.java

Method names should not contain underscores
358
public void set_mu02(double mu02)
Method names should not contain underscores
462
public void set_mu03(double mu03)

openCVLibrary24133/src/main/java/org/opencv/imgproc/Subdiv2D.java

Method names should not contain underscores
334
private static native double[] getVertex_1(long nativeObj, int vertex);

openCVLibrary24133/src/main/java/org/opencv/ml/CvNormalBayesClassifier.java

Method names should not contain underscores
227
private static native long CvNormalBayesClassifier_2(long trainData_nativeObj, long responses_nativeObj);

photoview/src/main/java/uk/co/senab/photoview/PhotoViewAttacher.java

Avoid really long classes.
50
public class PhotoViewAttacher implements IPhotoView, View.OnTouchListener,
Fields should be declared at the top of the class, before any method declarations, constructors, initializers or inner classes.
142
private OnMatrixChangedListener mMatrixChangeListener;
Use one line for each declaration, it enhances code readability.
754
float deltaX = 0, deltaY = 0;