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[BAEL-9555] - Created a core-java-modules folder

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amit2103
2019-05-05 17:22:09 +05:30
parent 8b63b0d90a
commit 3bae5e5334
1480 changed files with 25600 additions and 5594 deletions
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26
core-java-modules/core-java-sun/.gitignore vendored Normal file
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*.class
0.*
#folders#
/target
/neoDb*
/data
/src/main/webapp/WEB-INF/classes
*/META-INF/*
.resourceCache
# Packaged files #
*.jar
*.war
*.ear
# Files generated by integration tests
*.txt
backup-pom.xml
/bin/
/temp
#IntelliJ specific
.idea/
*.iml

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core-java-modules/core-java-sun/README.md Normal file
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=========
## Core Java Cookbooks and Examples
### Relevant Articles:
- [Creating a Java Compiler Plugin](http://www.baeldung.com/java-build-compiler-plugin)
- [Guide to sun.misc.Unsafe](http://www.baeldung.com/java-unsafe)

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core-java-modules/core-java-sun/pom.xml Normal file
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<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.baeldung</groupId>
<artifactId>core-java-sun</artifactId>
<version>0.1.0-SNAPSHOT</version>
<name>core-java-sun</name>
<packaging>jar</packaging>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-java</artifactId>
<version>0.0.1-SNAPSHOT</version>
<relativePath>../../parent-java</relativePath>
</parent>
<dependencies>
<!-- utils -->
<dependency>
<groupId>net.sourceforge.collections</groupId>
<artifactId>collections-generic</artifactId>
<version>${collections-generic.version}</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-collections4</artifactId>
<version>${commons-collections4.version}</version>
</dependency>
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>${commons-io.version}</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>${commons-lang3.version}</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-math3</artifactId>
<version>${commons-math3.version}</version>
</dependency>
<dependency>
<groupId>org.decimal4j</groupId>
<artifactId>decimal4j</artifactId>
<version>${decimal4j.version}</version>
</dependency>
<dependency>
<groupId>org.bouncycastle</groupId>
<artifactId>bcprov-jdk15on</artifactId>
<version>${bouncycastle.version}</version>
</dependency>
<dependency>
<groupId>org.unix4j</groupId>
<artifactId>unix4j-command</artifactId>
<version>${unix4j.version}</version>
</dependency>
<dependency>
<groupId>com.googlecode.grep4j</groupId>
<artifactId>grep4j</artifactId>
<version>${grep4j.version}</version>
</dependency>
<!-- web -->
<!-- marshalling -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>${jackson.version}</version>
</dependency>
<!-- logging -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</version>
</dependency>
<dependency> <!-- needed to bridge to slf4j for projects that use the log4j APIs directly -->
<groupId>org.slf4j</groupId>
<artifactId>log4j-over-slf4j</artifactId>
<version>${org.slf4j.version}</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>${lombok.version}</version>
<scope>provided</scope>
</dependency>
<!-- test scoped -->
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
<version>${assertj.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.jayway.awaitility</groupId>
<artifactId>awaitility</artifactId>
<version>${avaitility.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
<version>${commons-codec.version}</version>
</dependency>
<dependency>
<groupId>org.javamoney</groupId>
<artifactId>moneta</artifactId>
<version>${moneta.version}</version>
</dependency>
<dependency>
<groupId>org.owasp.esapi</groupId>
<artifactId>esapi</artifactId>
<version>${esapi.version}</version>
</dependency>
<dependency>
<groupId>com.sun.messaging.mq</groupId>
<artifactId>fscontext</artifactId>
<version>${fscontext.version}</version>
</dependency>
<dependency>
<groupId>com.codepoetics</groupId>
<artifactId>protonpack</artifactId>
<version>${protonpack.version}</version>
</dependency>
<dependency>
<groupId>one.util</groupId>
<artifactId>streamex</artifactId>
<version>${streamex.version}</version>
</dependency>
<dependency>
<groupId>io.vavr</groupId>
<artifactId>vavr</artifactId>
<version>${vavr.version}</version>
</dependency>
<dependency>
<groupId>org.openjdk.jmh</groupId>
<artifactId>jmh-core</artifactId>
<version>${jmh-core.version}</version>
</dependency>
<dependency>
<groupId>org.openjdk.jmh</groupId>
<artifactId>jmh-generator-annprocess</artifactId>
<version>${jmh-generator.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>${spring-web.version}</version>
</dependency>
<dependency>
<groupId>com.sun</groupId>
<artifactId>tools</artifactId>
<version>${sun-tools.version}</version>
<scope>system</scope>
<systemPath>${java.home}/../lib/tools.jar</systemPath>
</dependency>
</dependencies>
<build>
<finalName>core-java</finalName>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>${maven-jar-plugin.version}</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>libs/</classpathPrefix>
<mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>${exec-maven-plugin.version}</version>
<configuration>
<executable>java</executable>
<mainClass>com.baeldung.outofmemoryerror.OutOfMemoryGCLimitExceed</mainClass>
<arguments>
<argument>-Xmx300m</argument>
<argument>-XX:+UseParallelGC</argument>
<argument>-classpath</argument>
<classpath />
<argument>com.baeldung.outofmemoryerror.OutOfMemoryGCLimitExceed</argument>
</arguments>
</configuration>
</plugin>
</plugins>
</build>
<profiles>
<profile>
<id>integration</id>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<executions>
<execution>
<phase>integration-test</phase>
<goals>
<goal>test</goal>
</goals>
<configuration>
<excludes>
<exclude>**/*ManualTest.java</exclude>
</excludes>
<includes>
<include>**/*IntegrationTest.java</include>
<include>**/*IntTest.java</include>
</includes>
</configuration>
</execution>
</executions>
<configuration>
<systemPropertyVariables>
<test.mime>json</test.mime>
</systemPropertyVariables>
</configuration>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<executions>
<execution>
<id>run-benchmarks</id>
<!-- <phase>integration-test</phase> -->
<phase>none</phase>
<goals>
<goal>exec</goal>
</goals>
<configuration>
<classpathScope>test</classpathScope>
<executable>java</executable>
<arguments>
<argument>-classpath</argument>
<classpath />
<argument>org.openjdk.jmh.Main</argument>
<argument>.*</argument>
</arguments>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>
</profiles>
<properties>
<!-- util -->
<guava.version>23.0</guava.version>
<commons-lang3.version>3.5</commons-lang3.version>
<bouncycastle.version>1.55</bouncycastle.version>
<commons-codec.version>1.10</commons-codec.version>
<commons-math3.version>3.6.1</commons-math3.version>
<decimal4j.version>1.0.3</decimal4j.version>
<commons-collections4.version>4.1</commons-collections4.version>
<collections-generic.version>4.01</collections-generic.version>
<unix4j.version>0.4</unix4j.version>
<grep4j.version>1.8.7</grep4j.version>
<fscontext.version>4.6-b01</fscontext.version>
<protonpack.version>1.13</protonpack.version>
<streamex.version>0.6.5</streamex.version>
<vavr.version>0.9.0</vavr.version>
<spring-web.version>4.3.4.RELEASE</spring-web.version>
<!-- testing -->
<assertj.version>3.6.1</assertj.version>
<avaitility.version>1.7.0</avaitility.version>
<!-- maven plugins -->
<maven-surefire-plugin.version>2.21.0</maven-surefire-plugin.version>
<sun-tools.version>1.8.0</sun-tools.version>
<maven-jar-plugin.version>3.0.2</maven-jar-plugin.version>
</properties>
</project>

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core-java-modules/core-java-sun/src/main/java/com/baeldung/.gitignore vendored Normal file
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*.class
#folders#
/target
/neoDb*
/data
/src/main/webapp/WEB-INF/classes
*/META-INF/*
# Packaged files #
*.jar
*.war
*.ear

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core-java-modules/core-java-sun/src/main/java/com/baeldung/README.md Normal file
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### Relevant Articles:

9
core-java-modules/core-java-sun/src/main/java/com/baeldung/javac/Positive.java Normal file
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package com.baeldung.javac;
import java.lang.annotation.*;
@Documented
@Retention(RetentionPolicy.CLASS)
@Target({ElementType.PARAMETER})
public @interface Positive {
}

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core-java-modules/core-java-sun/src/main/java/com/baeldung/javac/SampleJavacPlugin.java Normal file
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package com.baeldung.javac;
import com.sun.source.tree.MethodTree;
import com.sun.source.tree.VariableTree;
import com.sun.source.util.*;
import com.sun.tools.javac.api.BasicJavacTask;
import com.sun.tools.javac.code.TypeTag;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.TreeMaker;
import com.sun.tools.javac.util.Context;
import com.sun.tools.javac.util.Name;
import com.sun.tools.javac.util.Names;
import javax.tools.JavaCompiler;
import java.util.*;
import java.util.stream.Collectors;
import static com.sun.tools.javac.util.List.nil;
/**
* A {@link JavaCompiler javac} plugin which inserts {@code >= 0} checks into resulting {@code *.class} files
* for numeric method parameters marked by {@link Positive}
*/
public class SampleJavacPlugin implements Plugin {
public static final String NAME = "MyPlugin";
private static Set<String> TARGET_TYPES = new HashSet<>(Arrays.asList(
// Use only primitive types for simplicity
byte.class.getName(), short.class.getName(), char.class.getName(),
int.class.getName(), long.class.getName(), float.class.getName(), double.class.getName()));
@Override
public String getName() {
return NAME;
}
@Override
public void init(JavacTask task, String... args) {
Context context = ((BasicJavacTask) task).getContext();
task.addTaskListener(new TaskListener() {
@Override
public void started(TaskEvent e) {
}
@Override
public void finished(TaskEvent e) {
if (e.getKind() != TaskEvent.Kind.PARSE) {
return;
}
e.getCompilationUnit()
.accept(new TreeScanner<Void, Void>() {
@Override
public Void visitMethod(MethodTree method, Void v) {
List<VariableTree> parametersToInstrument = method.getParameters()
.stream()
.filter(SampleJavacPlugin.this::shouldInstrument)
.collect(Collectors.toList());
if (!parametersToInstrument.isEmpty()) {
// There is a possible case that more than one argument is marked by @Positive,
// as the checks are added to the method's body beginning, we process parameters RTL
// to ensure correct order.
Collections.reverse(parametersToInstrument);
parametersToInstrument.forEach(p -> addCheck(method, p, context));
}
// There is a possible case that there is a nested class declared in a method's body,
// hence, we want to proceed with method body AST as well.
return super.visitMethod(method, v);
}
}, null);
}
});
}
private boolean shouldInstrument(VariableTree parameter) {
return TARGET_TYPES.contains(parameter.getType().toString())
&& parameter.getModifiers().getAnnotations()
.stream()
.anyMatch(a -> Positive.class.getSimpleName().equals(a.getAnnotationType().toString()));
}
private void addCheck(MethodTree method, VariableTree parameter, Context context) {
JCTree.JCIf check = createCheck(parameter, context);
JCTree.JCBlock body = (JCTree.JCBlock) method.getBody();
body.stats = body.stats.prepend(check);
}
private static JCTree.JCIf createCheck(VariableTree parameter, Context context) {
TreeMaker factory = TreeMaker.instance(context);
Names symbolsTable = Names.instance(context);
return factory.at(((JCTree) parameter).pos)
.If(factory.Parens(createIfCondition(factory, symbolsTable, parameter)),
createIfBlock(factory, symbolsTable, parameter),
null);
}
private static JCTree.JCBinary createIfCondition(TreeMaker factory, Names symbolsTable, VariableTree parameter) {
Name parameterId = symbolsTable.fromString(parameter.getName().toString());
return factory.Binary(JCTree.Tag.LE,
factory.Ident(parameterId),
factory.Literal(TypeTag.INT, 0));
}
private static JCTree.JCBlock createIfBlock(TreeMaker factory, Names symbolsTable, VariableTree parameter) {
String parameterName = parameter.getName().toString();
Name parameterId = symbolsTable.fromString(parameterName);
String errorMessagePrefix = String.format("Argument '%s' of type %s is marked by @%s but got '",
parameterName, parameter.getType(), Positive.class.getSimpleName());
String errorMessageSuffix = "' for it";
return factory.Block(0, com.sun.tools.javac.util.List.of(
factory.Throw(
factory.NewClass(null, nil(),
factory.Ident(symbolsTable.fromString(IllegalArgumentException.class.getSimpleName())),
com.sun.tools.javac.util.List.of(factory.Binary(JCTree.Tag.PLUS,
factory.Binary(JCTree.Tag.PLUS, factory.Literal(TypeTag.CLASS, errorMessagePrefix),
factory.Ident(parameterId)),
factory.Literal(TypeTag.CLASS, errorMessageSuffix))), null))));
}
}

1
core-java-modules/core-java-sun/src/main/resources/META-INF/services/com.sun.source.util.Plugin Normal file
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com.baeldung.javac.SampleJavacPlugin

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core-java-modules/core-java-sun/src/main/resources/log4j.properties Normal file
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log4j.rootLogger=DEBUG, A1
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n

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core-java-modules/core-java-sun/src/main/resources/logback.xml Normal file
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<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<encoder>
<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
</pattern>
</encoder>
</appender>
<logger name="org.springframework" level="WARN" />
<logger name="org.springframework.transaction" level="WARN" />
<!-- in order to debug some marshalling issues, this needs to be TRACE -->
<logger name="org.springframework.web.servlet.mvc" level="WARN" />
<root level="INFO">
<appender-ref ref="STDOUT" />
</root>
</configuration>

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core-java-modules/core-java-sun/src/test/java/com/baeldung/javac/SampleJavacPluginIntegrationTest.java Normal file
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package com.baeldung.javac;
import org.junit.Test;
import static org.junit.Assert.assertEquals;
public class SampleJavacPluginIntegrationTest {
private static final String CLASS_TEMPLATE =
"package com.baeldung.javac;\n" +
"\n" +
"public class Test {\n" +
" public static %1$s service(@Positive %1$s i) {\n" +
" return i;\n" +
" }\n" +
"}\n" +
"";
private TestCompiler compiler = new TestCompiler();
private TestRunner runner = new TestRunner();
@Test(expected = IllegalArgumentException.class)
public void givenInt_whenNegative_thenThrowsException() throws Throwable {
compileAndRun(double.class,-1);
}
@Test(expected = IllegalArgumentException.class)
public void givenInt_whenZero_thenThrowsException() throws Throwable {
compileAndRun(int.class,0);
}
@Test
public void givenInt_whenPositive_thenSuccess() throws Throwable {
assertEquals(1, compileAndRun(int.class, 1));
}
private Object compileAndRun(Class<?> argumentType, Object argument) throws Throwable {
String qualifiedClassName = "com.baeldung.javac.Test";
byte[] byteCode = compiler.compile(qualifiedClassName, String.format(CLASS_TEMPLATE, argumentType.getName()));
return runner.run(byteCode, qualifiedClassName, "service", new Class[] {argumentType}, argument);
}
}

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core-java-modules/core-java-sun/src/test/java/com/baeldung/javac/SimpleClassFile.java Normal file
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package com.baeldung.javac;
import javax.tools.SimpleJavaFileObject;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URI;
/** Holds compiled byte code in a byte array */
public class SimpleClassFile extends SimpleJavaFileObject {
private ByteArrayOutputStream out;
public SimpleClassFile(URI uri) {
super(uri, Kind.CLASS);
}
@Override
public OutputStream openOutputStream() throws IOException {
return out = new ByteArrayOutputStream();
}
public byte[] getCompiledBinaries() {
return out.toByteArray();
}
}

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core-java-modules/core-java-sun/src/test/java/com/baeldung/javac/SimpleFileManager.java Normal file
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package com.baeldung.javac;
import javax.tools.*;
import java.net.URI;
import java.util.ArrayList;
import java.util.List;
/** Adapts {@link SimpleClassFile} to the {@link JavaCompiler} */
public class SimpleFileManager extends ForwardingJavaFileManager<StandardJavaFileManager> {
private final List<SimpleClassFile> compiled = new ArrayList<>();
public SimpleFileManager(StandardJavaFileManager delegate) {
super(delegate);
}
@Override
public JavaFileObject getJavaFileForOutput(Location location,
String className,
JavaFileObject.Kind kind,
FileObject sibling)
{
SimpleClassFile result = new SimpleClassFile(URI.create("string://" + className));
compiled.add(result);
return result;
}
/**
* @return compiled binaries processed by the current class
*/
public List<SimpleClassFile> getCompiled() {
return compiled;
}
}

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core-java-modules/core-java-sun/src/test/java/com/baeldung/javac/SimpleSourceFile.java Normal file
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package com.baeldung.javac;
import javax.tools.SimpleJavaFileObject;
import java.net.URI;
/** Exposes given test source to the compiler. */
public class SimpleSourceFile extends SimpleJavaFileObject {
private final String content;
public SimpleSourceFile(String qualifiedClassName, String testSource) {
super(URI.create(String.format("file://%s%s",
qualifiedClassName.replaceAll("\\.", "/"),
Kind.SOURCE.extension)),
Kind.SOURCE);
content = testSource;
}
@Override
public CharSequence getCharContent(boolean ignoreEncodingErrors) {
return content;
}
}

35
core-java-modules/core-java-sun/src/test/java/com/baeldung/javac/TestCompiler.java Normal file
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package com.baeldung.javac;
import javax.tools.JavaCompiler;
import javax.tools.ToolProvider;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.List;
import static java.util.Arrays.asList;
import static java.util.Collections.singletonList;
public class TestCompiler {
public byte[] compile(String qualifiedClassName, String testSource) {
StringWriter output = new StringWriter();
JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
SimpleFileManager fileManager = new SimpleFileManager(compiler.getStandardFileManager(
null,
null,
null
));
List<SimpleSourceFile> compilationUnits = singletonList(new SimpleSourceFile(qualifiedClassName, testSource));
List<String> arguments = new ArrayList<>();
arguments.addAll(asList("-classpath", System.getProperty("java.class.path"),
"-Xplugin:" + SampleJavacPlugin.NAME));
JavaCompiler.CompilationTask task = compiler.getTask(output,
fileManager,
null,
arguments,
null,
compilationUnits);
task.call();
return fileManager.getCompiled().iterator().next().getCompiledBinaries();
}
}

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core-java-modules/core-java-sun/src/test/java/com/baeldung/javac/TestRunner.java Normal file
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package com.baeldung.javac;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
public class TestRunner {
public Object run(byte[] byteCode,
String qualifiedClassName,
String methodName,
Class<?>[] argumentTypes,
Object... args)
throws Throwable
{
ClassLoader classLoader = new ClassLoader() {
@Override
protected Class<?> findClass(String name) throws ClassNotFoundException {
return defineClass(name, byteCode, 0, byteCode.length);
}
};
Class<?> clazz;
try {
clazz = classLoader.loadClass(qualifiedClassName);
} catch (ClassNotFoundException e) {
throw new RuntimeException("Can't load compiled test class", e);
}
Method method;
try {
method = clazz.getMethod(methodName, argumentTypes);
} catch (NoSuchMethodException e) {
throw new RuntimeException("Can't find the 'main()' method in the compiled test class", e);
}
try {
return method.invoke(null, args);
} catch (InvocationTargetException e) {
throw e.getCause();
}
}
}

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core-java-modules/core-java-sun/src/test/java/com/baeldung/unsafe/CASCounter.java Normal file
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package com.baeldung.unsafe;
import sun.misc.Unsafe;
import java.lang.reflect.Field;
class CASCounter {
private final Unsafe unsafe;
private volatile long counter = 0;
private long offset;
private Unsafe getUnsafe() throws IllegalAccessException, NoSuchFieldException {
Field f = Unsafe.class.getDeclaredField("theUnsafe");
f.setAccessible(true);
return (Unsafe) f.get(null);
}
public CASCounter() throws Exception {
unsafe = getUnsafe();
offset = unsafe.objectFieldOffset(CASCounter.class.getDeclaredField("counter"));
}
public void increment() {
long before = counter;
while (!unsafe.compareAndSwapLong(this, offset, before, before + 1)) {
before = counter;
}
}
public long getCounter() {
return counter;
}
}

39
core-java-modules/core-java-sun/src/test/java/com/baeldung/unsafe/OffHeapArray.java Normal file
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package com.baeldung.unsafe;
import sun.misc.Unsafe;
import java.lang.reflect.Field;
class OffHeapArray {
private final static int BYTE = 1;
private long size;
private long address;
private Unsafe getUnsafe() throws IllegalAccessException, NoSuchFieldException {
Field f = Unsafe.class.getDeclaredField("theUnsafe");
f.setAccessible(true);
return (Unsafe) f.get(null);
}
OffHeapArray(long size) throws NoSuchFieldException, IllegalAccessException {
this.size = size;
address = getUnsafe().allocateMemory(size * BYTE);
}
public void set(long i, byte value) throws NoSuchFieldException, IllegalAccessException {
getUnsafe().putByte(address + i * BYTE, value);
}
public int get(long idx) throws NoSuchFieldException, IllegalAccessException {
return getUnsafe().getByte(address + idx * BYTE);
}
public long size() {
return size;
}
void freeMemory() throws NoSuchFieldException, IllegalAccessException {
getUnsafe().freeMemory(address);
}
}

125
core-java-modules/core-java-sun/src/test/java/com/baeldung/unsafe/UnsafeUnitTest.java Normal file
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package com.baeldung.unsafe;
import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;
import sun.misc.Unsafe;
import java.io.IOException;
import java.lang.reflect.Field;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.stream.IntStream;
import static junit.framework.Assert.assertTrue;
import static junit.framework.TestCase.assertEquals;
public class UnsafeUnitTest {
private Unsafe unsafe;
@Before
public void setup() throws NoSuchFieldException, IllegalAccessException {
Field f = Unsafe.class.getDeclaredField("theUnsafe");
f.setAccessible(true);
unsafe = (Unsafe) f.get(null);
}
@Test
public void givenClass_whenInitializeIt_thenShouldHaveDifferentStateWhenUseUnsafe() throws IllegalAccessException, InstantiationException {
//when
InitializationOrdering o1 = new InitializationOrdering();
assertEquals(o1.getA(), 1);
//when
InitializationOrdering o3 = (InitializationOrdering) unsafe.allocateInstance(InitializationOrdering.class);
assertEquals(o3.getA(), 0);
}
@Test
public void givenPrivateMethod_whenUsingUnsafe_thenCanModifyPrivateField() throws NoSuchFieldException {
//given
SecretHolder secretHolder = new SecretHolder();
//when
Field f = secretHolder.getClass().getDeclaredField("SECRET_VALUE");
unsafe.putInt(secretHolder, unsafe.objectFieldOffset(f), 1);
//then
assertTrue(secretHolder.secretIsDisclosed());
}
@Test(expected = IOException.class)
public void givenUnsafeThrowException_whenThrowCheckedException_thenNotNeedToCatchIt() {
unsafe.throwException(new IOException());
}
@Test
@Ignore // Uncomment for local
public void givenArrayBiggerThatMaxInt_whenAllocateItOffHeapMemory_thenSuccess() throws NoSuchFieldException, IllegalAccessException {
//given
long SUPER_SIZE = (long) Integer.MAX_VALUE * 2;
OffHeapArray array = new OffHeapArray(SUPER_SIZE);
//when
int sum = 0;
for (int i = 0; i < 100; i++) {
array.set((long) Integer.MAX_VALUE + i, (byte) 3);
sum += array.get((long) Integer.MAX_VALUE + i);
}
long arraySize = array.size();
array.freeMemory();
//then
assertEquals(arraySize, SUPER_SIZE);
assertEquals(sum, 300);
}
@Test
public void givenUnsafeCompareAndSwap_whenUseIt_thenCounterYildCorrectLockFreeResults() throws Exception {
//given
int NUM_OF_THREADS = 1_000;
int NUM_OF_INCREMENTS = 10_000;
ExecutorService service = Executors.newFixedThreadPool(NUM_OF_THREADS);
CASCounter casCounter = new CASCounter();
//when
IntStream.rangeClosed(0, NUM_OF_THREADS - 1)
.forEach(i -> service.submit(() -> IntStream
.rangeClosed(0, NUM_OF_INCREMENTS - 1)
.forEach(j -> casCounter.increment())));
service.shutdown();
service.awaitTermination(1, TimeUnit.MINUTES);
//then
assertEquals(NUM_OF_INCREMENTS * NUM_OF_THREADS, casCounter.getCounter());
}
class InitializationOrdering {
private long a;
public InitializationOrdering() {
this.a = 1;
}
public long getA() {
return this.a;
}
}
class SecretHolder {
private int SECRET_VALUE = 0;
public boolean secretIsDisclosed() {
return SECRET_VALUE == 1;
}
}
}

13
core-java-modules/core-java-sun/src/test/resources/.gitignore vendored Normal file
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*.class
#folders#
/target
/neoDb*
/data
/src/main/webapp/WEB-INF/classes
*/META-INF/*
# Packaged files #
*.jar
*.war
*.ear