diff --git a/gradle.properties b/gradle.properties
index cc0c15f08d..61ecfd8f7b 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -14,7 +14,6 @@ collections_version=0.3.4
 intellij_plugin_version=0.6.4
 jacoco_version=0.8.5
 commons_lang_version=3.11
-commons_io_version=2.8.0
 kotlin_logging_version=1.8.3
 ktor_version=1.4.1
 clikt_version=3.2.0
diff --git a/utbot-core/src/main/kotlin/org/utbot/common/FileUtil.kt b/utbot-core/src/main/kotlin/org/utbot/common/FileUtil.kt
index cab4e7ff33..45e1a0248c 100644
--- a/utbot-core/src/main/kotlin/org/utbot/common/FileUtil.kt
+++ b/utbot-core/src/main/kotlin/org/utbot/common/FileUtil.kt
@@ -223,6 +223,15 @@ object FileUtil {
         this.parentFile.mkdirs()
         this.createNewFile()
     }
+
+    // https://stackoverflow.com/a/68822715
+    fun byteCountToDisplaySize(bytes: Long): String =
+        when {
+            bytes >= 1 shl 30 -> "%.1f GB".format(bytes / (1 shl 30))
+            bytes >= 1 shl 20 -> "%.1f MB".format(bytes / (1 shl 20))
+            bytes >= 1 shl 10 -> "%.0f kB".format(bytes / (1 shl 10))
+            else -> "$bytes bytes"
+        }
 }
 
 /**
diff --git a/utbot-framework/build.gradle b/utbot-framework/build.gradle
index 526110da95..211b9f1132 100644
--- a/utbot-framework/build.gradle
+++ b/utbot-framework/build.gradle
@@ -37,16 +37,12 @@ dependencies {
     testImplementation project(':utbot-analytics')
 
     // used for testing code generation
-    testImplementation group: 'commons-io', name: 'commons-io', version: commons_io_version
     testImplementation group: 'junit', name: 'junit', version: junit4_version
     testImplementation group: 'org.junit.platform', name: 'junit-platform-console-standalone', version: junit4_platform_version
     testImplementation group: 'org.mockito', name: 'mockito-core', version: mockito_version
     testImplementation group: 'org.testng', name: 'testng', version: testng_version
     testImplementation group: 'org.mockito', name: 'mockito-inline', version: mockito_inline_version
 
-    testCompile group: 'org.mockito', name: 'mockito-inline', version: mockito_inline_version
-    testCompile group: 'org.apache.logging.log4j', name: 'log4j-core', version: log4j2_version
-
     z3native group: 'com.microsoft.z3', name: 'z3-native-win64', version: z3_version, ext: 'zip'
     z3native group: 'com.microsoft.z3', name: 'z3-native-linux64', version: z3_version, ext: 'zip'
     z3native group: 'com.microsoft.z3', name: 'z3-native-osx', version: z3_version, ext: 'zip'
diff --git a/utbot-framework/src/main/kotlin/org/utbot/engine/selectors/strategies/GraphViz.kt b/utbot-framework/src/main/kotlin/org/utbot/engine/selectors/strategies/GraphViz.kt
index 057fc70977..489b665f7c 100644
--- a/utbot-framework/src/main/kotlin/org/utbot/engine/selectors/strategies/GraphViz.kt
+++ b/utbot-framework/src/main/kotlin/org/utbot/engine/selectors/strategies/GraphViz.kt
@@ -1,24 +1,23 @@
 package org.utbot.engine.selectors.strategies
 
+import mu.KotlinLogging
+import org.utbot.common.FileUtil.createNewFileWithParentDirectories
 import org.utbot.engine.CALL_DECISION_NUM
 import org.utbot.engine.Edge
 import org.utbot.engine.ExecutionState
 import org.utbot.engine.InterProceduralUnitGraph
+import org.utbot.engine.isLibraryNonOverriddenClass
 import org.utbot.engine.isReturn
 import org.utbot.engine.selectors.PathSelector
 import org.utbot.engine.stmts
 import org.utbot.framework.UtSettings.copyVisualizationPathToClipboard
+import soot.jimple.Stmt
+import soot.toolkits.graph.ExceptionalUnitGraph
 import java.awt.Toolkit
 import java.awt.datatransfer.StringSelection
 import java.io.FileWriter
 import java.nio.file.Files
 import java.nio.file.Paths
-import mu.KotlinLogging
-import org.apache.commons.io.FileUtils
-import org.utbot.engine.isLibraryNonOverriddenClass
-import org.utbot.engine.isOverridden
-import soot.jimple.Stmt
-import soot.toolkits.graph.ExceptionalUnitGraph
 
 private val logger = KotlinLogging.logger {}
 
@@ -51,10 +50,17 @@ class GraphViz(
         val classLoader = GraphViz::class.java.classLoader
 
         for (file in requiredFileNames) {
-            FileUtils.copyInputStreamToFile(
-                classLoader.getResourceAsStream("html/$file"),
-                Paths.get(graphVisDirectory.toString(), file).toFile()
-            )
+            classLoader.getResourceAsStream("html/$file").use { inputStream ->
+                val path = Paths.get(graphVisDirectory.toString(), file)
+                val targetFile = path.toFile()
+                targetFile.createNewFileWithParentDirectories()
+
+                targetFile.outputStream().use { targetOutputStream ->
+                    inputStream?.copyTo(targetOutputStream) ?: logger.error {
+                        "Could not start a visualization because of missing resource html/$file"
+                    }
+                }
+            }
         }
         FileWriter(graphJs).use {
             it.write(
diff --git a/utbot-framework/src/test/kotlin/org/utbot/framework/codegen/CompilationAndRunUtils.kt b/utbot-framework/src/test/kotlin/org/utbot/framework/codegen/CompilationAndRunUtils.kt
index abe6b7805d..ac27d92c7b 100644
--- a/utbot-framework/src/test/kotlin/org/utbot/framework/codegen/CompilationAndRunUtils.kt
+++ b/utbot-framework/src/test/kotlin/org/utbot/framework/codegen/CompilationAndRunUtils.kt
@@ -4,7 +4,7 @@ import org.utbot.framework.plugin.api.CodegenLanguage
 import java.io.File
 import java.nio.file.Path
 import mu.KotlinLogging
-import org.apache.commons.io.FileUtils
+import org.utbot.common.FileUtil
 
 data class ClassUnderTest(
     val testClassSimpleName: String,
@@ -29,7 +29,7 @@ fun writeTest(
     val targetDir = classUnderTest.generatedTestFile.parentFile
     targetDir.mkdirs()
     logger.info {
-        "File size for ${classUnderTest.testClassSimpleName}: ${FileUtils.byteCountToDisplaySize(testContents.length.toLong())}"
+        "File size for ${classUnderTest.testClassSimpleName}: ${FileUtil.byteCountToDisplaySize(testContents.length.toLong())}"
     }
     classUnderTest.generatedTestFile.writeText(testContents)
     return classUnderTest.generatedTestFile
diff --git a/utbot-junit-contest/build.gradle b/utbot-junit-contest/build.gradle
index 82dd1e1cb9..92c678f76c 100644
--- a/utbot-junit-contest/build.gradle
+++ b/utbot-junit-contest/build.gradle
@@ -56,7 +56,6 @@ dependencies {
 
     implementation "com.github.UnitTestBot:soot:${soot_commit_hash}"
     implementation group: 'org.apache.commons', name: 'commons-exec', version: '1.2'
-    implementation group: 'commons-io', name: 'commons-io', version: commons_io_version
     implementation group: 'io.github.microutils', name: 'kotlin-logging', version: kotlin_logging_version
     implementation group: 'org.jsoup', name: 'jsoup', version: '1.6.2'
     testImplementation fileTree(dir: 'src/main/resources/projects/', include: '*/*.jar')
diff --git a/utbot-junit-contest/src/main/kotlin/org/utbot/contest/Contest.kt b/utbot-junit-contest/src/main/kotlin/org/utbot/contest/Contest.kt
index 4b563a31c4..0a2d36f670 100644
--- a/utbot-junit-contest/src/main/kotlin/org/utbot/contest/Contest.kt
+++ b/utbot-junit-contest/src/main/kotlin/org/utbot/contest/Contest.kt
@@ -16,7 +16,7 @@ import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.withTimeoutOrNull
 import kotlinx.coroutines.yield
 import mu.KotlinLogging
-import org.apache.commons.io.FileUtils
+import org.utbot.common.FileUtil
 import org.utbot.common.bracket
 import org.utbot.common.info
 import org.utbot.engine.EngineController
@@ -453,7 +453,7 @@ private fun prepareClass(kotlinClass: KClass<*>, methodNameFilter: String?): Lis
 }
 
 fun writeTestClass(cut: ClassUnderTest, testSetsAsString: String) {
-    logger.info { "File size for ${cut.testClassSimpleName}: ${FileUtils.byteCountToDisplaySize(testSetsAsString.length.toLong())}" }
+    logger.info { "File size for ${cut.testClassSimpleName}: ${FileUtil.byteCountToDisplaySize(testSetsAsString.length.toLong())}" }
     cut.generatedTestFile.parentFile.mkdirs()
     cut.generatedTestFile.writeText(testSetsAsString, charset)
 }
diff --git a/utbot-junit-contest/src/main/kotlin/org/utbot/contest/TestClassWriter.kt b/utbot-junit-contest/src/main/kotlin/org/utbot/contest/TestClassWriter.kt
index 645d9339d3..53b6c7bff2 100644
--- a/utbot-junit-contest/src/main/kotlin/org/utbot/contest/TestClassWriter.kt
+++ b/utbot-junit-contest/src/main/kotlin/org/utbot/contest/TestClassWriter.kt
@@ -4,7 +4,7 @@ import org.utbot.framework.codegen.Import
 import org.utbot.framework.codegen.StaticImport
 import org.utbot.framework.plugin.api.UtMethod
 import mu.KotlinLogging
-import org.apache.commons.io.FileUtils
+import org.utbot.common.FileUtil
 
 private val logger = KotlinLogging.logger {}
 
@@ -91,7 +91,7 @@ class TestClassWriter(
             insert(lastIndexOf("}"), tests)
             insert(lastIndexOf("}"), utils)
         }
-        logger.info { "File size for ${cut.testClassSimpleName}: ${FileUtils.byteCountToDisplaySize(codeBuilder.length.toLong())}" }
+        logger.info { "File size for ${cut.testClassSimpleName}: ${FileUtil.byteCountToDisplaySize(codeBuilder.length.toLong())}" }
         cut.generatedTestFile.writeText(codeBuilder.toString(), charset)
     }
 
diff --git a/utbot-sample/build.gradle b/utbot-sample/build.gradle
index 7a5d55d38b..add9e2f5c1 100644
--- a/utbot-sample/build.gradle
+++ b/utbot-sample/build.gradle
@@ -20,7 +20,6 @@ dependencies {
 //    testImplementation group: 'org.mockito', name: 'mockito-core', version: '3.5.13'
 
     testImplementation group: 'org.mockito', name: 'mockito-inline', version: '4.0.0'
-    testCompile "org.mockito:mockito-inline:+"
 }
 
 java {