[ATK-4416]: update guava version (#3906)

1. update guava version to 32.1.2-jre
    2. fix npe warning

pom.xml

@@ -78,7 +78,7 @@
         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>
-            <version>29.0-jre</version>
+            <version>32.1.2-jre</version>
         </dependency>
         <dependency>
             <groupId>com.alibaba</groupId>

src/main/java/com/actiontech/dble/memory/unsafe/utils/JavaUtils.java

@@ -24,6 +24,7 @@ import org.slf4j.LoggerFactory;
 
 import java.io.File;
 import java.io.IOException;
+import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -150,7 +151,7 @@ public final class JavaUtils {
             }
 
             // If suffix is valid use that, otherwise none was provided and use the default passed
-            return unit.convert(val, suffix != null ? TIME_SUFFIXES.get(suffix) : unit);
+            return unit.convert(val, suffix != null ? Optional.ofNullable(TIME_SUFFIXES.get(suffix)).orElse(unit) : unit);
         } catch (NumberFormatException e) {
             String timeError = "Time must be specified as seconds (s), " +
                     "milliseconds (ms), microseconds (us), minutes (m or min), hour (h), or day (d). " +
@@ -228,7 +229,7 @@ public final class JavaUtils {
                 }
 
                 // If suffix is valid use that, otherwise none was provided and use the default passed
-                return unit.convertFrom(val, suffix != null ? BYTE_SUFFIXES.get(suffix) : unit);
+                return unit.convertFrom(val, suffix != null ? Optional.ofNullable(BYTE_SUFFIXES.get(suffix)).orElse(unit) : unit);
             } else if (fractionMatcher.matches()) {
                 throw new NumberFormatException("Fractional values are not supported. Input was: " +
                         fractionMatcher.group(1));