Log to a log file config

ethereumj-core/pom.xml

@@ -131,6 +131,13 @@ mvn clean package -Dmaven.test.skip=true
             <artifactId>log4j</artifactId>
             <version>1.2.17</version>
         </dependency>
+
+        <dependency>
+            <groupId>log4j</groupId>
+            <artifactId>apache-log4j-extras</artifactId>
+            <version>1.2.17</version>
+        </dependency>
+
         <dependency>
             <groupId>com.yuvalshavit</groupId>
             <artifactId>antlr-denter</artifactId>

ethereumj-core/src/main/resources/log4j.properties

@@ -1,5 +1,5 @@
 # Root logger option
-log4j.rootLogger=DEBUG, stdout
+log4j.rootLogger=DEBUG, stdout, file
 
 # Direct log messages to stdout
 log4j.appender.stdout=org.apache.log4j.ConsoleAppender
@@ -7,6 +7,12 @@ log4j.appender.stdout.Target=System.out
 log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
 log4j.appender.stdout.layout.ConversionPattern= %d{HH:mm:ss} [%c{1}]  %m%n
 
+log4j.appender.file=org.apache.log4j.rolling.RollingFileAppender
+log4j.appender.file.layout=org.apache.log4j.PatternLayout
+log4j.appender.file.layout.ConversionPattern= %d{HH:mm:ss} [%c{1}]  %m%n
+log4j.appender.file.RollingPolicy=org.apache.log4j.rolling.TimeBasedRollingPolicy
+log4j.appender.file.RollingPolicy.FileNamePattern=./logs/ethereum_%d{yyyy-MM-dd}_h%d{HH}.log
+
 # filter noisy classes
 log4j.logger.org.ethereum.net = INFO
 log4j.logger.peerdiscovery = FATAL
@@ -18,3 +24,6 @@ log4j.logger.VM = DEBUG
 log4j.logger.main = INFO
 log4j.logger.state = DEBUG
 log4j.logger.blockchain = DEBUG
+log4j.logger.ui = DEBUG
+log4j.logger.gas = DEBUG
+