Package org.apache.tools.ant.util

Class JavaEnvUtils

java.lang.Object

org.apache.tools.ant.util.JavaEnvUtils

public final class JavaEnvUtils
extends Object

A set of helper methods related to locating executables or checking conditions of a given Java installation.

Starting with Java 10 we've stopped adding JAVA_ and VERSION_ attributes for new major version numbers of the JVM.

Since:

Ant 1.5

Field Summary

Fields

Modifier and Type	Field	Description
static final String	JAVA_1_0	Version constant for Java 1.0
static final String	JAVA_1_1	Version constant for Java 1.1
static final String	JAVA_1_2	Version constant for Java 1.2
static final String	JAVA_1_3	Version constant for Java 1.3
static final String	JAVA_1_4	Version constant for Java 1.4
static final String	JAVA_1_5	Version constant for Java 1.5
static final String	JAVA_1_6	Version constant for Java 1.6
static final String	JAVA_1_7	Version constant for Java 1.7
static final String	JAVA_1_8	Version constant for Java 1.8
static final String	JAVA_1_9	Deprecated. use #JAVA_9 instead
static final String	JAVA_10	Version constant for Java 10
static final String	JAVA_11	Version constant for Java 11
static final String	JAVA_12	Version constant for Java 12
static final String	JAVA_9	Version constant for Java 9
static final int	VERSION_1_0	Number Version constant for Java 1.0
static final int	VERSION_1_1	Number Version constant for Java 1.1
static final int	VERSION_1_2	Number Version constant for Java 1.2
static final int	VERSION_1_3	Number Version constant for Java 1.3
static final int	VERSION_1_4	Number Version constant for Java 1.4
static final int	VERSION_1_5	Number Version constant for Java 1.5
static final int	VERSION_1_6	Number Version constant for Java 1.6
static final int	VERSION_1_7	Number Version constant for Java 1.7
static final int	VERSION_1_8	Number Version constant for Java 1.8
static final int	VERSION_1_9	Deprecated. use #VERSION_9 instead
static final int	VERSION_10	Number Version constant for Java 10
static final int	VERSION_11	Number Version constant for Java 11
static final int	VERSION_12	Number Version constant for Java 12
static final int	VERSION_9	Number Version constant for Java 9

Method Summary

Modifier and Type	Method	Description
static File	createVmsJavaOptionFile(String[] cmds)	Writes the command into a temporary DCL script and returns the corresponding File object.
static String	getJavaHome()	Return the value of ${java.home}
static String	getJavaVersion()	Returns the version of Java this class is running under.
static int	getJavaVersionNumber()	Deprecated. use #getParsedJavaVersion instead
static String	getJdkExecutable(String command)	Finds an executable that is part of a JDK installation based on the java.home system property.
static String	getJreExecutable(String command)	Finds an executable that is part of a JRE installation based on the java.home system property.
static Vector<String>	getJrePackages()	get a vector of strings of packages built into that platforms runtime jar(s)
static Vector<String>	getJrePackageTestCases()	Testing helper method; kept here for unification of changes.
static DeweyDecimal	getParsedJavaVersion()	Returns the version of Java this class is running under.
static boolean	isApacheHarmony()	Checks whether the current VM is Apache Harmony.
static boolean	isAtLeastJavaVersion(String version)	Compares the current Java version to the passed in String - assumes the argument is one of the constants defined in this class.
static boolean	isClasspathBased()	Checks whether the current Java VM is GNU Classpath
static boolean	isGij()	Checks whether the current Java VM is the GNU interpreter gij or we are running in a gcj precompiled binary.
static boolean	isJavaVersion(String version)	Compares the current Java version to the passed in String - assumes the argument is one of the constants defined in this class.
static boolean	isKaffe()	Checks whether the current Java VM is Kaffe.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

JAVA_1_0

public static final String JAVA_1_0

Version constant for Java 1.0

See Also:

• Constant Field Values

VERSION_1_0

public static final int VERSION_1_0

Number Version constant for Java 1.0

See Also:

• Constant Field Values

JAVA_1_1

public static final String JAVA_1_1

Version constant for Java 1.1

See Also:

• Constant Field Values

VERSION_1_1

public static final int VERSION_1_1

Number Version constant for Java 1.1

See Also:

• Constant Field Values

JAVA_1_2

public static final String JAVA_1_2

Version constant for Java 1.2

See Also:

• Constant Field Values

VERSION_1_2

public static final int VERSION_1_2

Number Version constant for Java 1.2

See Also:

• Constant Field Values

JAVA_1_3

public static final String JAVA_1_3

Version constant for Java 1.3

See Also:

• Constant Field Values

VERSION_1_3

public static final int VERSION_1_3

Number Version constant for Java 1.3

See Also:

• Constant Field Values

JAVA_1_4

public static final String JAVA_1_4

Version constant for Java 1.4

See Also:

• Constant Field Values

VERSION_1_4

public static final int VERSION_1_4

Number Version constant for Java 1.4

See Also:

• Constant Field Values

JAVA_1_5

public static final String JAVA_1_5

Version constant for Java 1.5

See Also:

• Constant Field Values

VERSION_1_5

public static final int VERSION_1_5

Number Version constant for Java 1.5

See Also:

• Constant Field Values

JAVA_1_6

public static final String JAVA_1_6

Version constant for Java 1.6

See Also:

• Constant Field Values

VERSION_1_6

public static final int VERSION_1_6

Number Version constant for Java 1.6

See Also:

• Constant Field Values

JAVA_1_7

public static final String JAVA_1_7

Version constant for Java 1.7

See Also:

• Constant Field Values

VERSION_1_7

public static final int VERSION_1_7

Number Version constant for Java 1.7

See Also:

• Constant Field Values

JAVA_1_8

public static final String JAVA_1_8

Version constant for Java 1.8

See Also:

• Constant Field Values

VERSION_1_8

public static final int VERSION_1_8

Number Version constant for Java 1.8

See Also:

• Constant Field Values

JAVA_1_9

@Deprecated
public static final String JAVA_1_9

Deprecated.

use #JAVA_9 instead

Version constant for Java 1.9

See Also:

• Constant Field Values

VERSION_1_9

@Deprecated
public static final int VERSION_1_9

Deprecated.

use #VERSION_9 instead

Number Version constant for Java 1.9

See Also:

• Constant Field Values

JAVA_9

public static final String JAVA_9

Version constant for Java 9

Since:

Ant 1.9.8

See Also:

• Constant Field Values

VERSION_9

public static final int VERSION_9

Number Version constant for Java 9

Since:

Ant 1.9.8

See Also:

• Constant Field Values

JAVA_10

public static final String JAVA_10

Version constant for Java 10

Since:

Ant 1.10.7

See Also:

• Constant Field Values

VERSION_10

public static final int VERSION_10

Number Version constant for Java 10

Since:

Ant 1.10.7

See Also:

• Constant Field Values

JAVA_11

public static final String JAVA_11

Version constant for Java 11

Since:

Ant 1.10.7

See Also:

• Constant Field Values

VERSION_11

public static final int VERSION_11

Number Version constant for Java 11

Since:

Ant 1.10.7

See Also:

• Constant Field Values

JAVA_12

public static final String JAVA_12

Version constant for Java 12

Since:

Ant 1.10.7

See Also:

• Constant Field Values

VERSION_12

public static final int VERSION_12

Number Version constant for Java 12

Since:

Ant 1.10.7

See Also:

• Constant Field Values

Method Details

getJavaVersion

public static String getJavaVersion()

Returns the version of Java this class is running under.

Up until Java 8 Java version numbers were 1.VERSION - e.g. 1.8.x for Java 8, starting with Java 9 it became 9.x.

Returns:

the version of Java as a String, e.g. "1.6" or "9"

getJavaVersionNumber

@Deprecated
public static int getJavaVersionNumber()

Deprecated.

use #getParsedJavaVersion instead

Returns the version of Java this class is running under.

This number can be used for comparisons.

Returns:

the version of Java as a number 10x the major/minor, e.g Java1.5 has a value of 15 and Java9 the value 90 - major will be 1 for all versions of Java prior to Java 9, minor will be 0 for all versions of Java starting with Java 9.

getParsedJavaVersion

public static DeweyDecimal getParsedJavaVersion()

Returns the version of Java this class is running under.

This number can be used for comparisons.

Returns:

the version of Java as major.minor, e.g Java1.5 has a value of 1.5 and Java9 the value 9 - major will be 1 for all versions of Java prior to Java 9, minor will be 0 for all versions of Java starting with Java 9.

isJavaVersion

public static boolean isJavaVersion(String version)

Compares the current Java version to the passed in String - assumes the argument is one of the constants defined in this class. Note that Ant now requires JDK 1.8+ so JAVA_1_0 through JAVA_1_7 need no longer be tested for.

Parameters:

version - the version to check against the current version.

Returns:

true if the version of Java is the same as the given version.

Since:

Ant 1.5

isAtLeastJavaVersion

public static boolean isAtLeastJavaVersion(String version)

Compares the current Java version to the passed in String - assumes the argument is one of the constants defined in this class. Note that Ant now requires JDK 1.8+ so JAVA_1_0 through JAVA_1_7 need no longer be tested for.

Parameters:

version - the version to check against the current version.

Returns:

true if the version of Java is the same or higher than the given version.

Since:

Ant 1.7

isKaffe

public static boolean isKaffe()

Checks whether the current Java VM is Kaffe.

Returns:

true if the current Java VM is Kaffe.

Since:

Ant 1.6.3

See Also:

• https://github.com/kaffe/kaffe

isClasspathBased

public static boolean isClasspathBased()

Checks whether the current Java VM is GNU Classpath

Returns:

true if the version of Java is GNU Classpath

Since:

Ant 1.9.1

isGij

public static boolean isGij()

Checks whether the current Java VM is the GNU interpreter gij or we are running in a gcj precompiled binary.

Returns:

true if the current Java VM is gcj/gij.

Since:

Ant 1.8.2

isApacheHarmony

public static boolean isApacheHarmony()

Checks whether the current VM is Apache Harmony.

Returns:

true if the current VM is Apache Harmony.

Since:

Ant 1.8.2

getJreExecutable

public static String getJreExecutable(String command)

Finds an executable that is part of a JRE installation based on the java.home system property.

java, keytool, policytool, orbd, rmid, rmiregistry, servertool and tnameserv are JRE executables on Sun based JRE's.

You typically find them in JAVA_HOME/jre/bin if JAVA_HOME points to your JDK installation. JDK < 1.2 has them in the same directory as the JDK executables.

Parameters:

command - the java executable to find.

Returns:

the path to the command.

Since:

Ant 1.5

getJdkExecutable

public static String getJdkExecutable(String command)

Finds an executable that is part of a JDK installation based on the java.home system property.

You typically find them in JAVA_HOME/bin if JAVA_HOME points to your JDK installation.

Parameters:

command - the java executable to find.

Returns:

the path to the command.

Since:

Ant 1.5

getJrePackageTestCases

public static Vector<String> getJrePackageTestCases()

Testing helper method; kept here for unification of changes.

Returns:

a list of test classes depending on the java version.

getJrePackages

public static Vector<String> getJrePackages()

get a vector of strings of packages built into that platforms runtime jar(s)

Returns:

list of packages.

createVmsJavaOptionFile

public static File createVmsJavaOptionFile(String[] cmds)
                                    throws IOException

Writes the command into a temporary DCL script and returns the corresponding File object. It is the job of the caller to delete the file on exit.

Parameters:

cmds - the command.

Returns:

the file containing the command.

Throws:

IOException - if there is an error writing to the file.

getJavaHome

public static String getJavaHome()

Return the value of ${java.home}

Returns:

the java home value.