diff --git a/examples/NSGAIIAsAnEvolutionaryAlgorithm.jl b/examples/NSGAIIAsAnEvolutionaryAlgorithm.jl
index c34283a..22a2eaf 100644
--- a/examples/NSGAIIAsAnEvolutionaryAlgorithm.jl
+++ b/examples/NSGAIIAsAnEvolutionaryAlgorithm.jl
@@ -25,8 +25,9 @@ function main()
 
     solver.variation = CrossoverAndMutationVariation(offspringPopulationSize, crossover, mutation)
     solver.selection = BinaryTournamentSelection(solver.variation.matingPoolSize, DefaultDominanceComparator())
-    solver.replacement = RankingAndDensityEstimatorReplacement(DominanceRanking(DefaultDominanceComparator()), CrowdingDistanceDensityEstimator())
 
+    solver.replacement = RankingAndDensityEstimatorReplacement(DominanceRanking(DefaultDominanceComparator()), CrowdingDistanceDensityEstimator())
+    
     startingTime = Dates.now()
     optimize(solver)
     endTime = Dates.now()
diff --git a/examples/NSGAIIWithStandardSettings.jl b/examples/NSGAIIWithStandardSettings.jl
index 3c395d2..a871ba7 100644
--- a/examples/NSGAIIWithStandardSettings.jl
+++ b/examples/NSGAIIWithStandardSettings.jl
@@ -8,6 +8,7 @@ function main()
     problem = ZDT1()
 
     solver::NSGAII = NSGAII()
+    solver.problem = problem
     solver.populationSize = 100
 
     solver.termination = TerminationByEvaluations(25000)
diff --git a/src/algorithm/evolutionaryAlgorithm.jl b/src/algorithm/evolutionaryAlgorithm.jl
index ff836f9..f80e08f 100644
--- a/src/algorithm/evolutionaryAlgorithm.jl
+++ b/src/algorithm/evolutionaryAlgorithm.jl
@@ -54,7 +54,6 @@ function evolutionaryAlgorithm(ea::EvolutionaryAlgorithm)
 
     notify(ea.observable, ea.status)
   end
-
   foundSolutions = population
   return foundSolutions
 end
diff --git a/src/component/evolutionaryAlgorithm/replacement.jl b/src/component/evolutionaryAlgorithm/replacement.jl
index a7e9ed5..5c4d09e 100644
--- a/src/component/evolutionaryAlgorithm/replacement.jl
+++ b/src/component/evolutionaryAlgorithm/replacement.jl
@@ -2,7 +2,7 @@ struct MuPlusLambdaReplacement <: Replacement
     comparator::Comparator
 end
 
-function replace_(replacement::MuPlusLambdaReplacement, x::Vector{S}, y::Vector{S}) where {S <: Solution}
+function replace_(replacement::MuPlusLambdaReplacement, x::Vector{S}, y::Vector{S}) where {S<:Solution}
     jointVector = vcat(x, y)
     sort!(jointVector, lt=((a, b) -> compare(replacement.comparator, a, b) <= 0))
     return jointVector[1:length(x)]
@@ -12,7 +12,7 @@ struct MuCommaLambdaReplacement <: Replacement
     comparator::Comparator
 end
 
-function replace_(replacement::MuCommaLambdaReplacement, x::Vector{S}, y::Vector{S}) where {S <: Solution}
+function replace_(replacement::MuCommaLambdaReplacement, x::Vector{S}, y::Vector{S}) where {S<:Solution}
     @assert length(x) >= length(y) "The length of the x vector is lower than the length of the y vector"
 
     resultVector = Vector(y)
@@ -29,6 +29,7 @@ struct RankingAndDensityEstimatorReplacement <: Replacement
     RankingAndDensityEstimatorReplacement(ranking, densityEstimator) = new(ranking, densityEstimator, RankingAndCrowdingDistanceComparator())
 end
 
+
 function replace_(replacement::RankingAndDensityEstimatorReplacement, x::Vector{T}, y::Vector{T})::Vector{T} where {T<:Solution}
     jointVector = vcat(x, y)
 
@@ -41,4 +42,3 @@ function replace_(replacement::RankingAndDensityEstimatorReplacement, x::Vector{
     sort!(jointVector, lt=((x, y) -> compare(replacement.rankingAndDensityEstimatorComparator, x, y) < 0))
     return jointVector[1:length(x)]
 end
-
diff --git a/src/metajul.jl b/src/metajul.jl
index cb64fc7..0fd49b7 100644
--- a/src/metajul.jl
+++ b/src/metajul.jl
@@ -65,7 +65,7 @@ export variate
 include("component/evolutionaryAlgorithm/variation.jl")
 
 export MuCommaLambdaReplacement, MuPlusLambdaReplacement, RankingAndDensityEstimatorReplacement
-export replace_ 
+export replace_
 include("component/evolutionaryAlgorithm/replacement.jl")
 
 export ConstantValueStrategy
diff --git a/src/util/densityEstimator.jl b/src/util/densityEstimator.jl
index c54d3ff..f9a5bf4 100644
--- a/src/util/densityEstimator.jl
+++ b/src/util/densityEstimator.jl
@@ -61,7 +61,7 @@ function compute!(densityEstimator::CrowdingDistanceDensityEstimator, solutions:
             obj_range_inv = 1 / (maximumObjectiveValue - minimumObjectiveValue)
 
             for j in 2:(num_solutions-1)
-                @inbounds begin
+                begin
                     distance = (solutions[j+1].objectives[i] - solutions[j-1].objectives[i]) * obj_range_inv
                     distance += getCrowdingDistance(solutions[j])
                     setCrowdingDistance(solutions[j], distance)
diff --git a/src/util/ranking.jl b/src/util/ranking.jl
index 9e18a79..0e8021c 100644
--- a/src/util/ranking.jl
+++ b/src/util/ranking.jl
@@ -50,6 +50,7 @@ function compare(comparator::DominanceRankingComparator, solution1::Solution, so
 end
 
 function compute!(ranking::DominanceRanking, solutions::Array{T}) where {T <: Solution}
+    ranking.rank = []
     solutionsToRank = [solution for solution in solutions]
     rankCounter = 1