Added spoofJavaVersion option to bootstrap

Author: Lenni0451

bootstrap/src/main/java/net/raphimc/javadowngrader/bootstrap/AgentMain.java

@@ -23,6 +23,7 @@
 import net.raphimc.javadowngrader.impl.classtransform.util.ClassNameUtil;
 import net.raphimc.javadowngrader.runtime.RuntimeRoot;
 import net.raphimc.javadowngrader.util.Constants;
+import net.raphimc.javadowngrader.util.JavaVersion;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
@@ -65,6 +66,17 @@ public static void agentmain(String args, Instrumentation instrumentation) throw
         final TransformerManager transformerManager = new TransformerManager(new InstrumentationClassProvider(instrumentation));
         transformerManager.addBytecodeTransformer(new JavaDowngraderTransformer(transformerManager));
         transformerManager.hookInstrumentation(instrumentation);
+
+        if (System.getProperty("spoofJavaVersion") != null) {
+            final JavaVersion spoofedJavaVersion = JavaVersion.getByName(System.getProperty("spoofJavaVersion"));
+            if (spoofedJavaVersion == null) {
+                System.err.println("Unable to find version '" + System.getProperty("spoofJavaVersion") + "'");
+                System.exit(-1);
+            }
+            System.setProperty("java.version", spoofedJavaVersion.getFakeJavaVersionName());
+            System.setProperty("java.class.version", String.valueOf(spoofedJavaVersion.getVersion()));
+            System.setProperty("java.specification.version", spoofedJavaVersion.getFakeSpecificationVersionName());
+        }
     }
 
 }

…vadowngrader/standalone/JavaVersion.java …imc/javadowngrader/util/JavaVersion.javastandalone/src/main/java/net/raphimc/javadowngrader/standalone/JavaVersion.java renamed to src/main/java/net/raphimc/javadowngrader/util/JavaVersion.java standalone/src/main/java/net/raphimc/javadowngrader/standalone/JavaVersion.java renamed to src/main/java/net/raphimc/javadowngrader/util/JavaVersion.java

@@ -15,7 +15,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-package net.raphimc.javadowngrader.standalone;
+package net.raphimc.javadowngrader.util;
 
 import org.objectweb.asm.Opcodes;
 
@@ -37,14 +37,14 @@ public enum JavaVersion {
     JAVA_21("21", Opcodes.V21),
     ;
 
+    private final String name;
+    private final int version;
+
     JavaVersion(final String name, final int version) {
         this.name = name;
         this.version = version;
     }
 
-    private final String name;
-    private final int version;
-
     public String getName() {
         return this.name;
     }
@@ -53,4 +53,28 @@ public int getVersion() {
         return this.version;
     }
 
+    public String getFakeJavaVersionName() {
+        if (this.ordinal() <= JAVA_8.ordinal()) {
+            return "1." + this.name + ".0";
+        } else {
+            return this.version + ".0.0";
+        }
+    }
+
+    public String getFakeSpecificationVersionName() {
+        if (this.ordinal() <= JAVA_8.ordinal()) {
+            return "1." + this.name;
+        } else {
+            return this.name;
+        }
+    }
+
+    public static JavaVersion getByName(String name) {
+        name = name.toLowerCase().replace("java", "").replace("j", "");
+        for (JavaVersion version : JavaVersion.values()) {
+            if (version.getName().equalsIgnoreCase(name)) return version;
+        }
+        return null;
+    }
+
 }

standalone/src/main/java/net/raphimc/javadowngrader/standalone/JavaVersionEnumConverter.java

@@ -19,18 +19,19 @@
 
 import joptsimple.ValueConversionException;
 import joptsimple.ValueConverter;
+import net.raphimc.javadowngrader.util.JavaVersion;
 
 import java.util.StringJoiner;
 
 public class JavaVersionEnumConverter implements ValueConverter<JavaVersion> {
 
     @Override
-    public JavaVersion convert(String s) {
-        final String input = s.toLowerCase().replace("java", "").replace("j", "");
-        for (JavaVersion version : JavaVersion.values()) {
-            if (version.getName().equalsIgnoreCase(input)) return version;
+    public JavaVersion convert(final String name) {
+        final JavaVersion version = JavaVersion.getByName(name);
+        if (version == null) {
+            throw new ValueConversionException("Unable to find version '" + name + "'");
         }
-        throw new ValueConversionException("Unable to find version '" + s + "'");
+        return version;
     }
 
     @Override

standalone/src/main/java/net/raphimc/javadowngrader/standalone/Main.java

@@ -29,6 +29,7 @@
 import net.raphimc.javadowngrader.runtime.RuntimeRoot;
 import net.raphimc.javadowngrader.standalone.progress.MultiThreadedProgressBar;
 import net.raphimc.javadowngrader.standalone.util.GeneralUtil;
+import net.raphimc.javadowngrader.util.JavaVersion;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;