From cdbf9ecc9f4df2fb0827912095b3b7ddbfa4993b Mon Sep 17 00:00:00 2001
From: Andreas Schildbach <andreas.schildbach@bloq.com>
Date: Wed, 2 Jan 2019 16:20:23 +0100
Subject: [PATCH] Utils: Add isOpenJDKRuntime() and isJavaSERuntime() helpers.

---
 .../main/java/org/bitcoinj/core/Utils.java    | 38 ++++++++++++++++---
 .../java/org/bitcoinj/core/UtilsTest.java     |  7 ++++
 2 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/core/src/main/java/org/bitcoinj/core/Utils.java b/core/src/main/java/org/bitcoinj/core/Utils.java
index acf25da0..10b529e5 100644
--- a/core/src/main/java/org/bitcoinj/core/Utils.java
+++ b/core/src/main/java/org/bitcoinj/core/Utils.java
@@ -36,6 +36,8 @@ import java.util.concurrent.TimeUnit;
 import java.util.regex.Pattern;
 
 import org.bouncycastle.crypto.digests.RIPEMD160Digest;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import com.google.common.base.Joiner;
 import com.google.common.base.Splitter;
@@ -69,6 +71,8 @@ public class Utils {
 
     private static BlockingQueue<Boolean> mockSleepQueue;
 
+    private static final Logger log = LoggerFactory.getLogger(Utils.class);
+
     /**
      * <p>
      * The regular {@link BigInteger#toByteArray()} includes the sign bit of the number and
@@ -546,13 +550,35 @@ public class Utils {
         return maxItem;
     }
 
-    private static int isAndroid = -1;
+    private enum Runtime {
+        ANDROID, OPENJDK, ORACLE_JAVA
+    }
+
+    private static Runtime runtime = null;
+    static {
+        String runtimeProp = System.getProperty("java.runtime.name").toLowerCase(Locale.US);
+        if (runtimeProp == null)
+            runtime = null;
+        else if (runtimeProp.contains("android"))
+            runtime = Runtime.ANDROID;
+        else if (runtimeProp.contains("openjdk"))
+            runtime = Runtime.OPENJDK;
+        else if (runtimeProp.contains("java(tm) se"))
+            runtime = Runtime.ORACLE_JAVA;
+        else
+            log.info("Unknown java.runtime.name '{}'", runtimeProp);
+    }
+
     public static boolean isAndroidRuntime() {
-        if (isAndroid == -1) {
-            final String runtime = System.getProperty("java.runtime.name");
-            isAndroid = (runtime != null && runtime.equals("Android Runtime")) ? 1 : 0;
-        }
-        return isAndroid == 1;
+        return runtime == Runtime.ANDROID;
+    }
+
+    public static boolean isOpenJDKRuntime() {
+        return runtime == Runtime.OPENJDK;
+    }
+
+    public static boolean isOracleJavaRuntime() {
+        return runtime == Runtime.ORACLE_JAVA;
     }
 
     public static boolean isLinux() {
diff --git a/core/src/test/java/org/bitcoinj/core/UtilsTest.java b/core/src/test/java/org/bitcoinj/core/UtilsTest.java
index f1896241..5bea34ad 100644
--- a/core/src/test/java/org/bitcoinj/core/UtilsTest.java
+++ b/core/src/test/java/org/bitcoinj/core/UtilsTest.java
@@ -112,4 +112,11 @@ public class UtilsTest {
         byte[] actual = Utils.bigIntegerToBytes(b, 1);
         assertTrue(Arrays.equals(expected, actual));
     }
+
+    @Test
+    public void runtime() {
+        // This test assumes it is run within a Java runtime for desktop computers.
+        assertTrue(Utils.isOpenJDKRuntime() || Utils.isOracleJavaRuntime());
+        assertFalse(Utils.isAndroidRuntime());
+    }
 }