Package org.apache.tools.ant.util

Class JavaEnvUtils

java.lang.Object
org.apache.tools.ant.util.JavaEnvUtils
public final class JavaEnvUtils
extends java.lang.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 java.lang.String JAVA_1_0
    Version constant for Java 1.0
    static java.lang.String JAVA_1_1
    Version constant for Java 1.1
    static java.lang.String JAVA_1_2
    Version constant for Java 1.2
    static java.lang.String JAVA_1_3
    Version constant for Java 1.3
    static java.lang.String JAVA_1_4
    Version constant for Java 1.4
    static java.lang.String JAVA_1_5
    Version constant for Java 1.5
    static java.lang.String JAVA_1_6
    Version constant for Java 1.6
    static java.lang.String JAVA_1_7
    Version constant for Java 1.7
    static java.lang.String JAVA_1_8
    Version constant for Java 1.8
    static java.lang.String JAVA_1_9
    Deprecated.
    use #JAVA_9 instead
    static java.lang.String JAVA_10
    Version constant for Java 10
    static java.lang.String JAVA_11
    Version constant for Java 11
    static java.lang.String JAVA_12
    Version constant for Java 12
    static java.lang.String JAVA_9
    Version constant for Java 9
    static int VERSION_1_0
    Number Version constant for Java 1.0
    static int VERSION_1_1
    Number Version constant for Java 1.1
    static int VERSION_1_2
    Number Version constant for Java 1.2
    static int VERSION_1_3
    Number Version constant for Java 1.3
    static int VERSION_1_4
    Number Version constant for Java 1.4
    static int VERSION_1_5
    Number Version constant for Java 1.5
    static int VERSION_1_6
    Number Version constant for Java 1.6
    static int VERSION_1_7
    Number Version constant for Java 1.7
    static int VERSION_1_8
    Number Version constant for Java 1.8
    static int VERSION_1_9
    Deprecated.
    use #VERSION_9 instead
    static int VERSION_10
    Number Version constant for Java 10
    static int VERSION_11
    Number Version constant for Java 11
    static int VERSION_12
    Number Version constant for Java 12
    static int VERSION_9
    Number Version constant for Java 9

  • Method Summary

    Modifier and Type Method Description
    static java.io.File createVmsJavaOptionFile​(java.lang.String[] cmds)
    Writes the command into a temporary DCL script and returns the corresponding File object.
    static java.lang.String getJavaHome()
    Return the value of ${java.home}
    static java.lang.String getJavaVersion()
    Returns the version of Java this class is running under.
    static int getJavaVersionNumber()
    Deprecated.
    use #getParsedJavaVersion instead
    static java.lang.String getJdkExecutable​(java.lang.String command)
    Finds an executable that is part of a JDK installation based on the java.home system property.
    static java.lang.String getJreExecutable​(java.lang.String command)
    Finds an executable that is part of a JRE installation based on the java.home system property.
    static java.util.Vector<java.lang.String> getJrePackages()
    get a vector of strings of packages built into that platforms runtime jar(s)
    static java.util.Vector<java.lang.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​(java.lang.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​(java.lang.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

  • Method Details

    • getJavaVersion

      public static java.lang.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​(java.lang.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​(java.lang.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 java.lang.String getJreExecutable​(java.lang.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 java.lang.String getJdkExecutable​(java.lang.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 java.util.Vector<java.lang.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 java.util.Vector<java.lang.String> getJrePackages()
      get a vector of strings of packages built into that platforms runtime jar(s)
      Returns:
      list of packages.

    • createVmsJavaOptionFile

      public static java.io.File createVmsJavaOptionFile​(java.lang.String[] cmds) throws java.io.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:
      java.io.IOException - if there is an error writing to the file.

    • getJavaHome

      public static java.lang.String getJavaHome()
      Return the value of ${java.home}
      Returns:
      the java home value.