Get the apk (sample.apk) to specified(sample_1) folder and rename it to zip format (sample.zip) unzip(extract) that file with in the folder.
download the dex2jar from this link: http://code.google.com/p/dex2jar/downloads/list
copy this zip to sample_1 and unzip(extract) that file with in this folder..
download the java de compiler from this link: http://java.decompiler.free.fr/?q=jdgui
copy this to sample_1 and unzip(extract) that file with in this folder.
Open the dex2jar folder, copy source apk file within dex2jar folder.
Open the command prompt(browse your dex2jar folder) Type following code in command prompt
You will get sample_dex2jar.jar file within sample_1
Run the jd-gui.exe.
Click File-->select the sample_dex2jar.jar where it is stored.
Now you will get the all java code.