Could not find tools.jar. Please check that C:\Program Files\Java\jre1.8.0_151 contains a valid JDK installation

At last, here I found the solution.

I added jdk path org.gradle.java.home=C\:\\Program Files\\Java\\jdk1.8.0_144 to gradle.properties file and did a rebuild. It works now.

ERROR: Could not find tools.jar. Please check that C:\Program Files\Java\jre1.8.0_121 contains a valid JDK installation

Copy tools.jar from C:\Program Files\Java\jdk1.8.0_121\lib to C:\Program Files\Java\jre1.8\lib.

It’s resolved the problem now.

Just had this happen to me.

Apparently Java’s automatic updater installed and configured a new version of the JRE for me, while leaving the old JDK intact. So even though I did have a JDK, it didn’t match the currently “active” JRE, which was causing the error.

Download a matching version of the JDK to the JRE you currently have installed, (In OP’s case 151) That should do the trick.

I had the same problem and fixed it like this:

1. Install the JDK from the Oracle website with the same version number
   as the JRE if you didn’t already.
2. Furthermore add JAVA_HOME to the environment variables of Windows.
3. Restart your terminal or development environment to load the new JAVA_HOME value.