I am developing an embedded java application (jar) which consumed by Android application. (the Android device (API19) it's just the view, I imported the JAR with Gradle to my Android Studio's project).
I'm using H2 database (tested on Android) and I'm trying to use it with connection pool (tried C3P0 and HakiriCP).
Here is the jar pom file content (with HakiriCP):
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.app</groupId>
<artifactId>reactor</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<log4j.version>1.2.15</log4j.version>
<rx.version>1.3.8</rx.version>
<dbh2.version>1.4.196</dbh2.version>
<junit.version>4.7</junit.version>
<json.version>20180813</json.version>
<slf4j-log4j12.version>1.7.21</slf4j-log4j12.version>
<log4j.version>1.2.17</log4j.version>
</properties>
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>3.1.1</version>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/alternateLocation</outputDirectory>
<overWriteReleases>false</overWriteReleases>
<overWriteSnapshots>false</overWriteSnapshots>
<overWriteIfNewer>true</overWriteIfNewer>
<includeScope>provided</includeScope>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.1.1</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
</execution>
</executions>
<configuration>
<finalName>uber-${artifactId}-${version}</finalName>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<!-- https://mvnrepository.com/artifact/io.reactivex/rxjava -->
<dependency>
<groupId>io.reactivex</groupId>
<artifactId>rxjava</artifactId>
<version>${rx.version}</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.h2database/h2 -->
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<version>${dbh2.version}</version>
</dependency>
<dependency>
<groupId>com.zaxxer</groupId>
<artifactId>HikariCP-java7</artifactId>
<version>2.4.13</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.json/json -->
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>${json.version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${slf4j-log4j12.version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>${slf4j-log4j12.version}</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</version>
</dependency>
<!-- https://mvnrepository.com/artifact/log4j/apache-log4j-extras -->
<dependency>
<groupId>log4j</groupId>
<artifactId>apache-log4j-extras</artifactId>
<version>${log4j.version}</version>
</dependency>
<!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${junit.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.ghgande</groupId>
<artifactId>j2mod</artifactId>
<version>2.5.0</version>
<scope>system</scope>
<systemPath>${project.basedir}/src/main/resources/j2mod.jar</systemPath>
</dependency>
</dependencies>
</project>
To build the jar I used maven plugins (assembly, one-jar...) to make sure all dependencies are in the class path.
When I'm running the JAR everything is working well, but when I'm trying to run the Android application (with that jar) I'm getting some errors. Here is my Android project gradle file content:
apply plugin: 'com.android.application'
android {
compileSdkVersion 26
buildToolsVersion '27.0.3'
defaultConfig {
applicationId 'com.app.android'
minSdkVersion 19
targetSdkVersion 26
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
dataBinding {
enabled = true
}
productFlavors {
}
}
dependencies {
def lifecycle_version = "1.1.1"
implementation fileTree(include: ['*.jar'], dir: 'libs')
implementation 'com.android.support:appcompat-v7:26.1.0'
implementation 'com.android.support.constraint:constraint-layout:1.1.0'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
implementation 'com.android.support:recyclerview-v7:26.1.0'
implementation 'com.android.support:design:26.1.0'
implementation "android.arch.lifecycle:extensions:$lifecycle_version"
implementation (group: 'com.zaxxer', name: 'HikariCP-java7', version: '2.4.13')
implementation files('libs/reactor.jar')
}
The errors I'm getting are mostly Class-not-found Exception, such:
Caused by: java.lang.ClassNotFoundException: Class io.prometheus.client.Collector not found
In HakiriCP there are some dependencies which under provided scope so I tried to import those dependencies in my Android gradle file but I'm still getting errors such as:
10-03 10:55:17.960 18268-18281/com.atlantium.aio.android E/dalvikvm: Could not find class 'javax.naming.InitialContext', referenced from method com.zaxxer.hikari.HikariConfig.getObjectOrPerformJndiLookup
10-03 10:55:17.960 18268-18281/com.atlantium.aio.android W/dalvikvm: VFY: unable to resolve new-instance 4434 (Ljavax/naming/InitialContext;) in Lcom/zaxxer/hikari/HikariConfig;
10-03 10:55:17.960 18268-18281/com.atlantium.aio.android D/dalvikvm: VFY: replacing opcode 0x22 at 0x0004
10-03 10:55:17.960 18268-18281/com.atlantium.aio.android W/dalvikvm: VFY: unable to resolve exception class 4437 (Ljavax/naming/NamingException;)
VFY: unable to find exception handler at addr 0x11
VFY: rejected Lcom/zaxxer/hikari/HikariConfig;.getObjectOrPerformJndiLookup (Ljava/lang/Object;)Ljava/lang/Object;
VFY: rejecting opcode 0x0d at 0x0011
VFY: rejected Lcom/zaxxer/hikari/HikariConfig;.getObjectOrPerformJndiLookup (Ljava/lang/Object;)Ljava/lang/Object;
Verifier rejected class Lcom/zaxxer/hikari/HikariConfig;
Is there something I'm missing?
Is it possible to use JDBC connection pools on android? (according to Establish pooled connection to MySQL in android it's possible but still I can't get it work).
Maybe someone can recommend about another connection pool which tested on android?
Thanks
Update
According to H2 documentation:
Currently only the JDBC API is supported (it is planned to support the Android database API in future releases)......
Limitations: Using a connection pool is currently not supported, because the required javax.sql. classes are not available on Android.