Develop Reference

Unable to locate an executable at "/Library/Java/JavaVirtualMachines/..."

I want to install an NPM express generator:
sudo apt npm install -g express-generator
It throws the following error:
Unable to locate an executable at "/Library/Java/JavaVirtualMachines/openjdk-14.0.1.jdk/Contents/Home/bin/apt" (-1)
I installed Java in this path (it's not in the System/Library/ - maybe thats the issue?):
'MacintoshSSD/Library/Java/JavaVirtualMachines/openjdk-14.0.1.jdk/Contents/Home'
My .bash_profile looks like that:
export JAVA_HOME=$(/usr/libexec/java_home)
If I check JAVA_HOME it looks fine:
echo $JAVA_HOME
/Library/Java/JavaVirtualMachines/openjdk-14.0.1.jdk/Contents/Home
.. and Java version:
java --version
openjdk 14.0.1 2020-04-14
OpenJDK Runtime Environment (build 14.0.1+7)
OpenJDK 64-Bit Server VM (build 14.0.1+7, mixed mode, sharing)
Any idea why it still can find an exectuable?
I an other thread I read about a possible conflict between the pre-installed macOS Java-Version and the Orcalce Java-Version enter link description here but I couldn`t work it out..
And could you explain to me the difference between java_home and JAVA_HOME?

Sorry, I just saw what's wrong...
There used to be an apt tool in Java, but it's gone now. Your mistake is using the linux command line. On many linux systems, another tool called apt is used for installing software.
Check the npm documentation on how to install npm on your Mac, as there are different ways to do it.
Once npm is installed, run sudo npm install -g express-generator (no apt here).
Explanation of the error message
The Java apt-tool was removed in JDK 8. But as JAVA_HOME/bin is normally not on your PATH on Mac, apple provides simple wrappers for all the commands under JAVA_HOME. There still is such a wrapper for apt that tries to run a program with the same name from your Java installation. That's why you get that error message.
conflict between the pre-installed macOS Java-Version and the Orcalce Java-Version:
Apple stopped pre-installing Java in macOS 10.7 so this should not be an issue.
difference between java_home and JAVA_HOME:
JAVA_HOME is an environment variable that points to your Java installation. java_home is a utility program in macOS that makes it easier to correctly set up your JAVA_HOME by listing installed Java versions and the values to use for JAVA_HOME.

How to install Java(openjdk) on Ubuntu for React-native

I tried install open-jdk for react-native.But i encountered some problem. How can i solve it ? Thanks
$ sudo apt update
$ sudo apt install default-jdk
Reading package lists... Done
Building dependency tree
Reading state information... Done
default-jdk is already the newest version (2:1.11-68ubuntu1~18.04.1).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
5 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Setting up oracle-java11-installer-local (11.0.4-1~linuxuprising1) ...
Before installing this package,
please download the Oracle JDK 11 .tar.gz file
with the same version as this package (version 11.0.4),
and place it in /var/cache/oracle-jdk11-installer-local,
E.g.:
sudo mkdir -p /var/cache/oracle-jdk11-installer-local
sudo cp jdk-11.0.4_linux-x64_bin.tar.gz /var/cache/oracle-jdk11-
installer-local/
sha256sum mismatch jdk-11.0.4_linux-x64_bin.tar.gz
Oracle JDK 11 is NOT installed.
dpkg: error processing package oracle-java11-installer-local (--
configure):
installed oracle-java11-installer-local package post-installation
script subprocess returned error exit status 1
dpkg: dependency problems prevent configuration of default-jre:
default-jre depends on openjdk-11-jre; however:
Package openjdk-11-jre is not installed.
Package oracle-java12-installer which provides openjdk-11-jre is
not
installed.
Package oracle-java11-installer-local which provides openjdk-11-jre
is not configured yet.
Errors were encountered while processing:
oracle-java11-installer-local
default-jre
default-jdk
default-jre-headless
default-jdk-headless
E: Sub-process /usr/bin/dpkg returned an error code (1)
I tried remove java and java's repo and re-install but no response.
Sorry my English.
Edit
If i run this code:
java -version
give the output:
openjdk version "1.8.0_212"
OpenJDK Runtime Environment (build 1.8.0_212-8u212-b03-
0ubuntu1.18.04.1-b03)
OpenJDK 64-Bit Server VM (build 25.212-b03, mixed mode)
I don't use Java with Android Studio.

Try these commands:
add repository
sudo add-apt-repository ppa:openjdk-r/ppa
update the packages
sudo apt-get update
Install OpenJDK 8:
sudo apt-get install openjdk-8-jdk

GCP Datastore Emulator won't install on OpenJDK 10

I have a Ubuntu host on which i have installed OpenJDK 10 and Gloud SDK using APT. When i try to install 'google-cloud-sdk-datastore-emulator', i get the error shown below.
I found a thread on GCP GitHub that talks about this but its closed. Here - https://github.com/GoogleCloudPlatform/cloud-sdk-docker/issues/144
Anyone else having this issue?
Error -
# apt install google-cloud-sdk-datastore-emulator
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
google-cloud-sdk-datastore-emulator : Depends: openjdk-8-jdk but it is not installable
E: Unable to correct problems, you have held broken packages.
My Environment -
OS -
DISTRIB_RELEASE=18.04
DISTRIB_CODENAME=bionic
DISTRIB_DESCRIPTION="Ubuntu 18.04.2 LTS"
NAME="Ubuntu"
VERSION="18.04.2 LTS (Bionic Beaver)"
OpenJDK -
#java -version
openjdk version "10.0.2" 2018-07-17
OpenJDK Runtime Environment (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.4)
OpenJDK 64-Bit Server VM (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.4, mixed mode)
#javac -version
javac 10.0.2
#which java
/usr/bin/java
Gcloud sdk -
# gcloud -v
Google Cloud SDK 234.0.0
alpha 2019.02.08
beta 2019.02.08
bq 2.0.41
core 2019.02.08
gsutil 4.36
kubectl 2019.02.08

There's some issue with our debian package dependancy config.
Although if you install the emulator via gcloud command it should work:
gcloud components install cloud-datastore-emulator
(https://cloud.google.com/sdk/gcloud/reference/components/install)
Note the components manager doesn't work if sdk is insalled from other package managers. In this case you can remove it and install following the suggestion here: stackoverflow.com/questions/42697026
If for some other reason you do have to install via apt-get, https://serverfault.com/questions/250224 should help, basically avoid install openjdk by:
apt-get install google-cloud-sdk-datastore-emulator openjdk-8-jdk-
Note there's a "-" after the openjdk-8-jdk
Or you can follow the steps in the same thread to update package dependancy.

My solution involved using equivs to create a fake openjdk-8-jdk package (of course you need to make sure you have another JDK).
apt-get install equivs
equivs-control openjdk-8-jdk
vim openjdk-8-jdk # especially change the package name, but I also used 11.0.0 as a version (although it's probably not needed)
equivs-build openjdk-8-jdk
dpkg -i openjdk-8-jdk*.deb

gradle on command line [duplicate]

I'm working on MacOS and just starting with react-native.
One of the first steps to get started is to run: react-native run-android or react-native run-ios. But I'm getting this error:
react-native run-android
Result:
Scanning folders for symlinks in /Users/ric/myprojs/albums/node_modules (6ms)
Starting JS server...
Building and installing the app on the device (cd android && ./gradlew installDebug)...
FAILURE: Build failed with an exception.
* What went wrong:
Could not determine java version from '9.0.1'.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
Could not install the app on the device, read the error above for details.
Make sure you have an Android emulator running or a device connected and have
set up your Android development environment:
https://facebook.github.io/react-native/docs/android-setup.html
This is what I get when I run java --version:
java --version
Result:
java 9.0.1
Java(TM) SE Runtime Environment (build 9.0.1+11)
Java HotSpot(TM) 64-Bit Server VM (build 9.0.1+11, mixed mode)
mbp:albums ric$ java --version
java 9.0.1
Java(TM) SE Runtime Environment (build 9.0.1+11)
Java HotSpot(TM) 64-Bit Server VM (build 9.0.1+11, mixed mode)
Edit
My javac version:
javac --version
Result:
javac 9.0.1
Any idea on how to fix this?

In your PROJECT_PATH/android/gradle/wrapper/gradle-wrapper.properties file, update your distributionUrl to the following:
distributionUrl=https\://services.gradle.org/distributions/gradle-5.0-all.zip
See related gradle distributions documentation

Really the fastest way to get around this error is to use JDK 8. Except when you really need to use JDK9.
http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
Don't forget to change your enviroment variable JAVA_HOME to the new JDK version!

Make sure that you have JDK8 installed and then set JAVA_HOME into JDK8
for example:
export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_151.jdk/Contents/Home
or use .bash_* files to set this variable

vi ~/.bash_profile
Then add the following lines:
export ANDROID_HOME=$HOME/Library/Android/sdk
export PATH=$PATH:$ANDROID_HOME/tools
export PATH=$PATH:$ANDROID_HOME/tools/bin
export PATH=$PATH:$ANDROID_HOME/platform-tools
export JAVA_HOME=$(/usr/libexec/java_home -v 1.8)
Now source the file to make the above changes effective in the current shell:
source ~/.bash_profile

On MacOS, I ran the following commands:
brew cask uninstall java
brew tap caskroom/versions
brew cask install java8 "or just brew cask install java to install latest version"

I was getting this error, but for a more recent version of Java - 10.0.2.
To fix my error, I followed the steps mentioned by #Blacktoviche in this Github issue: https://github.com/facebook/react-native/issues/17688
When I opened the android folder inside my project via Android Studio, I was prompted with Android Gradle plugin update recommended. At the time, I was following a slightly outdated tutorial that told me to click Don't remind me again for this project.
However, as #Blacktoviche recommended in the github issue linked above, sometimes it's necessary to update the Gradle plugin. After updating, I also had to click Install Build Tools 27... and sync project (I don't remember the exact version).
After I followed these steps, I was able to successfully run my react native app on the Android Studio emulator.
Hope this helps someone!

---- December 2018 --- keep attention ---
React Native does not work with Java versions higher than 8, so you need to uninstall your 9.0.1 version. To do so, execute the following commands:
cd /Library/Java/JavaVirtualMachines/
ls -l
Identify the folder containing your Java Version, then remove it
sudo rm -rf jdk.x.x_xxx.jdk
After that you can download and install java 8 from oracle again. Refer to jdk8 download page

If you are using windows; Make sure you add your jdk path to the Environment path variable.
Then open your android folder from your react native project into android studio. It will update necessary things for you automatically.

I usually get this error when I forget to build the project using Android Studio. A simple sync and upgrading Gradle will do the work.

I solve this by downgrading my JDK to 8.

On Ubuntu, you should run these command lines in the terminal:
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt install oracle-java8-installer
sudo apt install oracle-java8-set-default

jni.h: No such file or directory

I have been following this tutorial, and at step 5, I am getting the following output from GCC:
HelloWorld.c:1:17: error: jni.h: No such file or directory
In file included from HelloWorld.c:3:
HelloWorld.h:15: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘void’
HelloWorld.c:5: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘void’
I know that he include directories vary from system to system, so I tried to adapt the command accordingly, but I cannot seem to find the correct directory on my system. I am using Ubuntu 10.04LTS.

Open up a terminal and type:
locate jni.h
That should tell you where every file called jni.h is on your system. I am on ubuntu 11.04, and it's located at:
/usr/lib/jvm/java-6-openjdk/include/jni.h
/usr/lib/jvm/java-6-sun-1.6.0.26/include/jni.h
You may also need to get it from the repos:
sudo apt-get install openjdk-6-jdk
should do the trick if you don't have it installed.

jni.h lives with JDK. For me it is: jdk1.6.0_25/include/.
And by default, I don't think Ubuntu would have JDK with development libraries, so download latest JDK version from Oracle and install it somewhere.
Or you can install openjdk as #Leif suggested if it works on 10.04 LTS. Although, I personally, prefer the one from Sun/Oracle.

In Ubuntu 14.04 run:
sudo apt-get install openjdk-7-jdk openjdk-7-jre-lib
Now, you have a headers into /usr/lib/jvm/java-7-openjdk-amd64/include
For OpenJDK 6:
sudo apt-get install openjdk-6-jdk openjdk-6-jre-lib